On the Cetacean Larynx, with Special Remarks on the
Laryngeal Sack of the Sei \Vhale and the ArytenoEpiglottideal Tube of the Sperm vVhale
byHiroshi Hosokawa
Department of Anatomy (Professor Dr. T. Ogawa),
Medical School, Universityof Tokyo.

Introduction
Since very early the larynx of the whales has, because of its peculiar
structure, attracted notice of many anatomists. The most striking peculiarities lies in the tube formed by the upward elongated epiglottic and arytenoid cartilages and dilated at its summit like a knob, protruding into thechoana. After Tyson (1680), who observed this tube for the first time in
Phocaena communis, a number of anatomists described this structure invarious kinds of whales, for instance, J. Hunter (1787) in the harbour
porpoise, dolphin, pottfisch and narwhal, Meckel (1833) in Delphinus andPhocaena, Stannius (1846) in Delphinus and Monodon, Vrolick (1848) inHyperoodon, Huxley (cited from Howes), Burmeister (1867), Howes (1879),
Rawitz (1900) and Boenninghaus (1902) in Phocaena communis, Murie(1871, 74) in Grampus rissoanus and Globicephalus, Watson and Young(1878-79) in Beluga leucas, Dubois (1886) in Hyderoodon, Tursiops, Phocaena, Delphinus and Globicephalus, and Benham (1901) in Cogia breviceps.
To the last mentioned author we owe probably the name " arytenoepiglottideal tube ".
Meanwhile it is worthy of notice that research materials of theseanatomists were always toothed whq.les. The question naturally arises,
whether the whalebone-whales have also the same tube in the larynx..
This problem was answered by Eugen Dubois (1886), who compared
the larynges of Hyperoodon, Tursiops, Phocaena, Delphinus and Globicephalus with that of a fetus of Balaenoptera Sibbaldii, and asserted thenon-existence of the aryteno·epiglottideal tube in the latter. Besides there
are, according to him, m1ny other differences in the larynx between
whalebone and toothed whales.
While engaging recently in the anatomical research up.on some whales,

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Hiroshi Hosokawa

I was much interested by the striking difference in the larynx between
two groups of the whales and was led to make some detailed inquiries
about this matter.
The following . materials have been hitherto examined by me in thisresearch. Whalebone whales :1. Balaenoptera borealis, 42 feet, female; 46 feet, female (at Ayukawa,
Miyagi Prefecture).
2. Balaenoptera musculus, fetuses of various lengths (in Antarctic
Ocean).
3. Balaenoptera physalus, fetuses of various lengths (in Antarctic Ocean).
Toothed whales:·
4. Physeter catodon, 32 feet, male; 36 feet, female (at Ayukawa).
5. Lagenorhynx obliquidens, male fetus of 51 cm length (at Kawana,
Shizuoka Prefecture).
6. Prodelphinus caeruleo-albus, 11 feet, male; 117 cm, female (atKawana).
7. Globicephalus melas, 15 feet, male; 16 feet, female (at Ayukawa).

In this1 paper I will treat mainly the larynx of the Sei whale (Balaenoptera borealis) and that of the Sperm whale (Physeter catodon); observations on the larynges of the others will be reported later.
I. Cartilages of the larynx
The larynx of the whales is constructed, as in other mammals, of the
cartilagenous framework and several muscles connecting the cartilages.
They form as a whole a tubular organ with the laryngeal cavity in it.
The inner surface is covered with the mucous membrane continuous withthat of the pharynx upwards and of the trachea downwards.
The laryngeal cartilages are five in number, three of which (thyroid,

cricoid, epiglottic) are unpaired and the rest two are paired (arytenoid). The
corniculate and the cuneiform cartilages do not exist as separated ones ..
At first the form of each cartilage will be mentioned, compared between
the Sei and the Sperm whale.
The THYROID cartilage
Sei whale: (fig. 1) Two laminae, right and left, of this cartilage arefused together iq_ the anterior middle line, there forming no sharp angle.

On the Cetacean Larynx

25

The cartilage is as a whole a plate concave behind and shaped like a
flying swallow, providing with four processes; the inferior corun, corresponding to wings of the swallow, is very well developed, projects caudally andmakes a joint with the cricoid. - The upwards directed superior cornu is
not so well developed. Between the superior horns of both sides a deep
V-shaped notch exists, separating partly the right and the left lamina(incisura thyreoidea cranialis). The caudal border has in the median line
a shallow notch (incisura thyreoidea caudalis).
The outer surface of the laminae, smooth and convex as a whole,shows no remarkable prominence. The thyreohyoid and sternothyreoid
muscles are attached to relatively small areas near the superior lateralborder of the lamina. The cricoarytenoid muscle inserts partly to theouter surface around the caudal notch, but for the greater part to theinner surface of this cartilage. To the inner surface are attached also
three muscles, thyreopharyngicus, thyi:eoarytaenoideus and thyreoepiglotticus. Moreover the posterior end of the inferior horr1° is connected withthe musculus cerato-cricoarytaenoideus dorsalis.
Sperm whale: (fig. 1') The thyroid is the largest cartilage in thelarynx of this whale, differing in shape very little from the homologous
structure in most of other mammals. Two laminae, right and left, arefused together at the middle front, forming a tolerably sharp angle, andthere we see the prominentia laryngica.
The superior horn is very slight, and .the inferior one is also not sowell developed as in. the Sei whale. Each lamina is irregularly triangularin shape ; its outer surface is not smooth, having along its upper border alineal crest, which courses downward to the middle portion of the lamina,
and is divided there in two crests ; one of them goes to the dorsal side,slightly inclining to the caudal direction, while the other runs ventrocaudally, and serves as insertion for the thyreohyoid and sternothyreoid
muscles. At the point, where the lineal crest changes its course from theupper border to the middle of the lamina, it surrounds a pore, foramen
thyreoideum, through which a nerve (the inner branch of then. laryngicus.
cranialis) and a vessel (a. laryngica cranialis) penetrate. Existence of sucha pore was mentioned already by Stannius in various whales, and by
Rawitz in Phocaena communis.
The inner surface of the lamina is nearly smooth and gives attachment

26

Hiroshi Hosokawa ·to the thyreopharyngeal and thyreoarytenoid muscles etc.
The EPIGLOTTic cartilage
Sei whale : (fig. 2) This elastic cartilage is not so hard as other larygeal
cartilages. Its upper half, not so dilated widely as in the human larynx,
is concave behind and convex in front. The lower half (petiolus epiglottidis) is long and thin, and directed to the cranial notch of the thyroid
cartilage.
Sperm whale: (fig. 2') This large cartilage is an elongated triangle
in shape seen from lateral, with an apex directed ventro··cranially, where
the hyo-epiglottic muscle is attached. The cranial apex is, seen from behind,triangular arid involved forwards.
The hind surface of this cartilage has three lineal longitudinal elevations, one in the median line and two others along the lateral margins ; thelatter meet with the lateral border of tihe arytenoid cartilage and areconnected with it by the mucous membrane, forming so together thea:r.yteno-epiglottideal tube.
The caudal end of this cartilage has a tubercle, whioh is connected tothe angle between two laminae of the thyroid cartilage, a little below thecranial noch. This connection is strengthened by soild ligamentous fibres.
The Cmcom cartilage
Seiwhale: (fig. 3) The name "cricoid" does not hold good for thiswhale, for the cricoid cartilage is not shaped lik;e a signet-ring as in othermammals, but its ventral half, corresponding to arcus, is completely deficient and the whole cartilage is merely a plate concave in .front. The
upper margin of this plate has a slight prominence at the middle, and alittle more laterad on each side an articular facet for the arytenoid cartilage.
Caudally it is directly united with the tracheal cartilages, forming
together the cricotracheal plate in the dorsal wall of larynx and trachea.
Lateral parts of this plate are partially separated by a longitudinal notchfrom the main medial portion and may be named " processus lateralis" ;the inner concave surface of this lateral process gives attachment to a
portion of muscles of the laryngeal sack, which will be mentioned later.
Moreover, the m. cricothyreoideus inserts to the outer surface of thisprocess, a little above its caudal end.'

On the Cetacean Larynx

27

Inner and outer surfaces of the cricoid cartilage, nearly smooth all over,have a slight crest along the median part of the outer surface, which runs
from the upper border downwards, remarkably dilating. Wide areas on
both sides of the crest are for insertion of the dorsal cricoarytenoid
muscles. The most caudal part of this area is connected with the criocopharyngeal muscle. A little more mediad than the upper end of the notch,
which demarcates the lateral process, there are artiCular facets for theinferior horns of the thyroid cartilage. This joint is not fully diarthrodial
but somewhat syndesmodial, strengthened behind by fibrous bands, while
the aryteno-cricoidal joint is diarthrodial, provided with the articular capsule.
Sperm whale: (fig. 3')
This whale has a completely ring-formed
cricoid cartilage, a very diferent circumstance therefore from the Sei whale.
This fact deserves special attention, for, according to Dubois, all of the
toothed whales· he examined, with the exception of Tursiops! have incompletely ring-formed cricoid cartilage ; in them the ventral portion is said tohave a fissure, though the fissure is not so broad as in whalebone whales.
Sanctis (1879) seems to have found in Physeter macrocephalus the same
matter as in Tursiops (cited from Dµbois); and Benham found also in an
adult male Cogia a completely ring-shaped 1cricoid catilage. In other toothed
whales examined by me the matter is quite the same as Dubois described~
Therefore, as to the cricoid cartilage there are ·two groups in the toothed
whales, one of which (Physeteridae etc.) has a completely ring-shaped
cricoid cartilage, while the other (Delphinidae and Hyperoodon) an incomplete one. The cricoid cartilage of the sperm whale is not united withthe tracheal cartilages, a distinct space filled with fibrous bands existing
between them.
The very thick posterior portion of .the cricoid cartilage gives attaehment to the dorsal cricoarytenoid muscle, while the middle portion of its
cranial border is connected with some fibres of the transverse arytenoid
muscle. The anterior part of this cartilage is narrow and somewhat thin,
but widens as it approaches the median line.
The ARYTENOID cartilages
Sei whale: (fig. 4) Each of the paired cartilages has two· processes
directed up and down (processus cranialis and proc. caudalis). The tongue·
shaped cranial one is thin in the transverse direction, while the caudal one

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Hiroshi Hosokawa

is dick and rounded. The pointed ends of the caudal processes are connected by fibrous tissue between both sides. The main part of the cartilage,
corpus, has a laterally directed large prominence, which corresponds
probably to the processus muscularis, giving attachment for the dorsal
cricoarytenoid muscle etc. The dorsal surface of this portion has an
oblique oval facet to articulate with the upper border of the cricoid
cartilage. The corpus has furthermore a crest along the medial border ofits ventral surface, probably homologous to the processus vocalis. · Uponthe relation of various muscles to this cartilage 1 want to refer it to theaccompanying figures.
Sperm whale: (fig. 4')
The most remarkable difference upon thearytenoid cartilage between Sperm and Sei whale is the absence of caudal
process in the former. In the Sperm whale the well developed cranial
processes of both sides, standing side by side on the cricoid cartilage, form
a concave furrow in front, and their upper ends are fused together into one
cartilage. Between the ventrolateral border of this process and the lateral
crest of the epiglottic cartilage a fold of mucous membrane (plica aryepiglottica) is stretched and thus the aryteno-epoglottideal tube is completed.
The CoRNICULATE and the CUNEIFORM cartilages
These cartilages could not be found in all the whales I have examined,
at least as separated ones. Almost all of the authors who have studied thelarynx of whales did not mention about them. Watson and Young denied
the existence of them in ·Beluga. But Howes remarked in a fetus of
Phocaena that the arytenoidi cartilage consists of two separated pieces,and the 'upper portiop. of the so-called arytenoid, which is prolonged into
the nasal passage, must represent an elongated cuneiform cartilage, theSantorinian element being absent. Negus (1928) agreed with Howes; he had
examined a reconstruction model of the larynx of a fetal Sperm whale,
which was 4.5 inches long, and finding two columns of mesenchymal,
cartilaginous cells lying above and slightly ventral to the arytenoids,
mentioned confidently· that these cell-groups would make the ca1tilages of
Wrisberg and, together with the epiglottis, constitute the peculiar laryngeal
tub.e. Of the Santorinian cartilage he denied its existence. In sm3.ll fetusesof Blue and Fin whales I examined minutely the cranial process of thearytaenoid, but no separated piece of the cartilage was found, and in a

On the Cetacean Larynx

29very small fetus (17 cm of length) of Megaptera nodosa, I saw that only the
corpus of the arytenoid consists of cartilaginous element, the cranial process
being formed merely of connective tissue.
The TRACHEAL cartilages
As these are closely related to the larynx, I will give a brief description of them.
Sei whale: (fig. 3) All of the tracheal cartilages are continuous witheach other and moreover, as mentioned above, with the cricoid cartilage intheir dorsal parts, forming altogether a single plate. In the lateral parts
they are however separated from each other by tranverse ·fissures and the·ventral portions are completely wanting. Though Dubois stated that only
the upper 4:-5 tracheal cartilages are fused with the cricoid in a fetus, of
B. Sibbaldii, in my observation of the Sei whale all of the eight cartilages
up to the bifurcatio trancheae form a single plate.
Sperm whale: (fig. 5') In this whale the tracheal cartilages are complete rings, and the i;nost cranial one is separate from the cricoid cartilage.
The upper three cartilages are fused together in the dorsal part~, but theothers are all separated from each other. The fact, that all of the tracheal
cartilages form complete rings, seems to be an exception in the whales.
For, according to Dubois,. the uppermost one (Hyperoodon) or two (Delphinus, Phocaena) tracheal cartilages are lacking of its ventral portion,
and also Watson and Young mentioned the same relation as to two or
three upper cartilages respectively for Beluga and Delphinus.
II. ' Muscles of the larynx
Laryngeal muscles of the Cetacea have been studied by a number ofanatomists, but their explanations are not always coincident. The differenceof opinions come, to my mind, partly from difference of the materials
treated. In fact, every species of the whales has more or less its own
structure. We must naturally consider seriously the differences between
toothed and whalebone whales. In the following my results upon laryngeal
muscles of the Sei and the Sperm whale will be mentioned.
Sei whale:
As in the case of other mammals, the laryngeal muscles are classified
also in this whale into two groups, extrinsic and intrinsic. The· extrinsic

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Hiroshi Hosokawa

muscles, connecting the larynx with neighbouring structures, are :Musculus sternothyreoideus (innervated by branches from the ansa
hypoglossi)
Musculus thyreohsi-oideus (ditto)
Musculus laryngopharyngicus (innervated .by branches of the plexus
pharyngicus)
Musculus hyoepiglcttious or baseohyoepiglotticus
The STERNOTHYREOIDEUS and the THYREOHYom:Eus belong to the so-called
infrahyoidal muscles and insert to the thyroid cartilage. The well developed
LARYNGOPHARYNGICUS consists of THYREO}'HARYNGICUS and CRICOPIIARYN·a1cus. The former arises from the frontolateral part of the inner surfaceof the thyroid cartilage and its massive fibres surround the pharynx tomeet with that of the opposite at the posterior median part of thepharyngeal wall, i. e. raphe pharyngis. The latter originates from thedorsolateral part .of the cricoid cartilage and, running up and medial wards,
terminates also at the raphe pharyngis. The unpaired HYOEPIGLOTTrcus
was described by Carte and Macalister (1868) in Balaenoptera rostrata, but
I could not see it in the Sei whale.
The intrinsic muscles are those, which begin and end within the larynx
itself. In the following I will describe them one by one.
( 1 ) M. CRrcOTHYREOIDEus; (fig. 5) This muscle arises from the outersurface of the lateral process of the cricoid cartilage and runs upward
and laterad, to insert on the medial border of the inferior horn of the
thyroid cartilage. It is not divided into two parts, pars recta and parsobiqua, as in the human larynx. This muscle is the only one in the wholelarynx, that is innervated by the cranial laryngeal nerve (fig. 18).
( 2) M. CRrcoARYTAENOIDEUs DoRSALrs; (figs. 6, 7) This muscle arises
mostly. from the posterior medial portion of the cricoid cartilage, partiallyalso from the caudal end of the inferior horn o~ the thyroid cartilage. Its
fibres converge upwards and laterad to reach the muscular process of thearytenoid cartilage. Because of the connection with the inferior horn, it
may be called better " m. ceratocricoarytaenoideus dorsalis ", the nameused already by Dubois.
( 3) M. ARYTAENOIDEus; (fig. 16) Tracing the fibres of m. cricoarytaenoideus dorsalis upwards, we come across muscle fibres running transversally between the arytenoid cartilages of both sides. The fibres ariseOn the Cetacean Larynx

31

f~om the dorsolateral margin of the cranial process of the arytenoid cartilage on one side and attain the corresponding part of the same cartilageof the other side. This muscle (m. arytaenoideus transversus of Dubois)
corresponds probably to the transversal part of m. arytaenoideus in thehuman larynx. The pars obliqua is not found in the cetacean larynx.
According to Dubois the most caudal part of the arytenoidal muscle iscovered by the upper part of the dorsal cricoarytenoid muscle, and moreover some fibres of the former are attached to the cricoid cartilage. On
this point I agree with Dubois, though the boundary between these two
muscles is not very distinct.
( 4 ) Muscle of the walls of the laryngeal sack (M. THYREOARYTAENOIDEUS,
M. CRICOARYTAENOIDEUS LATERAUS, M. ARYEPIGLOTTICUS, M. THYREOEPIGLOT'l'ICUS ) ; (figs. 5, 8, 9, 12-17)
As will be mentioned later, the Sei whale
has a large sack attached to the ventral wall of the laryngotrachea. It
communicates with the proper laryngeal cavity through a wide opening
which exists between the arytenoid cartilages of both sides. This laryngeal
sack has thick muscular walls and its muscles, cross-striated in nature,
are arranged so differently from the laryngeal muscles in other animals,that it is not easy to determine the homologies between them.

Carte and Macalister examined for the first time these muscles in
Balaenoptera rostrata with the conclusion that they belong to m. thyreoarytaenoideus. Dubois insisted that not only the thyreoarytenoid muscle
but also the m. cricoa:rytaenoideus lateralis takes part in the formation ofthis muscular wall. Thereafter Benham, studying a newborn female Balaenoptera rostrata, supported Carte and Macalister's opinion and denied theco-existence of the lateral cricoarytenoid muscle.
At any rate these muscles exhibit quite strange arrangem~nt in relation to the cartilages. In the Sei whale we see on the ventral surface ofthe larynx them. cricothyreoideus on both sides. Moreover,- massive muscle
fibres come into sight from behind the caudal ridge of the thyroid cartilage,
nmning downwards and ·being directed in the lateral parts somewaht
laterad. These muscles, which form the ventral and lateral walls of thelaryngeal sack, insert partly to the ventral ridges of the cricoid andtracheal cartilages, where these cartilages are defective in the ventral
portion. More cephalic and deep fibres of them reach the muscular processof the arytenoid cartilage.

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Hiroshi Hosokawa

The comparatively superficial muscular layer of the laryngeal sackcourses as a whole in the caudo-lateral direction ; I would call it "A-group"in the following description.
A deeper group of muscle fibres arises mainly from the ventral surfaceof the caudal process of the arytenoid cartilage and, diverging downwards,
forms a part of the ventral, lateral and to some extent the dorsal wallof the laryngeal sack (" B-group "). These fibres seem to have no insertion
to any cartilage, terminating within the muscular wall itself. The ventral
portion of them, running caudally and mediad, contrary to the caudal andlateral direction of the A-group, is interwoven in the median line between
both sides~
Such a division of superficial and deep layers is however not so distinct, and they form altogether the very thick wall of the laryngeal sack.
For this reason, the muscles were taken as a whole by Carte-Macalisterand Benham as the thyreoarytenoid muscle, while Dubois regarded probably
the B-group as the lateral cricoarytenoid muscle.
It seems certain from my observatfon that the walls of the .laryngeal
sack are mainly formed by the thyreoarytenoid muscle, but this muscle
has, because of the extraordinary development of the sack, additional
insertions to the cricoid and tracheal cartilages. As to the problem, whether the B-group corresponds to the lateral cricoarytenoid muscle, I cansay nothing confidently. The bare fact is that the superficial fibres are
directed somewhat differently than the deep fibres.
In addition to A- and B-group, some muscle fibres situated m a morecranial place arise from the inner surface of the thyroid cartilage andcourse almost horizontally, surrounding the sack from lateral to reach the
middle ventral part of the arytenoid cartilage (" C-group "). We see besides
other fibres in a more. cranial level, connecting the basal part of the upper
process of the arytenoid cartilage with the root of the epoglottis (" Dgroup "). These groups are however not very clearly separated from eachother, but form as a whole the thick wall of the laryngeal sack. I guessthat the D-group in my description may correspond to M. ARYEPIGLOTTICus
mentioned by Dubois and Benham respectively in the larynx of B. Sibbaldii
and B. rostrata, or the superior and inferior arytenoepiglottic muscle
described by Carte and Macalister in B. rostrata, while the C-group seems
not to have been specially remarked by prevfous authors. They have pro-

33

On the Cetacean Larynx

bably ·considered this group merely as a part of the thyreoarytaenoideus.
The THYREOEPIGLOTTIC muscle, which extends between the root of the· epigl?ttis and the. cranial border of the thyroid cartilage, makes also a partof the muscular walls of the laryngeal sack.
Innervation of the laryngeal muscles (fig.18) :Of all the laryngeal muscles in the Sei whale only the cricothyreoideus
receives the external branch of the N. LARYNmcus CRANIALis. This nervec;lescends along the lateral surface ·of the larynx and, changing its course
slightly mediad, crosses over the thyroid cartilage. It comes down along
the lateral ridge of the cricothyreoideus, and then terminat.es there. . Theinternal · branch of this nerve runs through the thick laryngopharyngeal
muscle and ends in the mucous membrane of the larynx.
The N. LARYNGrnus CAUDAUS is considerably thick, ascends as the n ..
recurrens in the furrow between trachea and resophagus, comes near to
the inferior horn of . the thyroid cartilage and, crossing over the here
arising m. ceratocricoq.rytaenoitleus dorsalis, passes under this horn, to reachthe laryngeal sack, where it is divided into several branches, some of which
innervate the m .. cricoarytaenoideus and others enter .into the thick wallsof the sack, ending in its· muscles. The ending occurs in such a .way,that the uppermost branches course under the caudal border of the thyroid
cartilage and attain. the m. arYtaenoideus transversus; the next branches goto the C- and D-group ; the lowermost _branches, running in the caudal
direction, terminate in the superficial and deep layers of A- and B-group,
and we can trace their small branches macroscopically up to the half levelof ·the sack.
· Thus it is certain that, as all the muscles of the walls of the laryngeal
sack are innervated by n. laryngicus caudalis, A-group of muscles, in spiteof its insertion to the cricoid and tracheal cartilages, does not belong to
the cricothyreoideus.

.

Sperm whale :Extrinsic muscles
M. 1 STERNCYTHYREornEus and M. THYREOHYornEus: Connecting placesof these muscles to the thyroid cartilage are shown in t.he accompaning
figures (fig. 1'-a, b).

34

Hiroshi Hosokawa

M. LARYNGOPHARYNGICUS : Of this muscle the thyreopharyngeal' partis well developed, but the cricopharyngeal part is not found at all.
M. HYoEPIGLOTTJcus: This unpaired musde arises from the hyoid bone·(probably from its median part) and inserts to the ventral angle. of theepiglottic cartilage.
M. PALATOPHARYNGICUS : The aryteno-epiglottideal tube, protruding
into the choana, is encircled at the height of . its neck by a muscularbundle, which lies within the choanal walls. This bundle, named by vonBaer (1826) as the palatopharyngeal muscle, is well developed also in the
Sperm whale. It must have an important meaning in relation to the function of the aryteno-epiglottideal tube. For, when it contracts, the communication between the naso-pharynx and the laryngeal cavity is shut out ; atthe same time the aditus laryngis must be closed completely. The meaningof such anatomical structures will be considered later.
Intrinsic muscles( 1) M. CiircOTHYREOIDEUS: Stannius (1M8) and Rawitz described thismusole in phocaena communis as a small muscular bundle ; also Dubois
and Macalister (1867) remarked the same in Hyperoodon and Globicephalus
svineval respectively. But according to Benham, this muscle was invisible
in Cogia. In the Sperm whale, too, I could not ascertain its existence.
Whether it is quite absent in this whale, I want to determine by further
researches.
( 2 ) M. CRicoARYTAENomEus DoRSALrs : (fig. 6') ·This is very well developed.
As in the Sei whale not only the dorsal surface of the cricoid · cartilage
but also the inferior horn of the thyroid cartilage gives rise to this muscle(m. ceratocricoarytaenoideus dorsalis).
Its partial connection with theinferior horn was already reported by Stannius and Dubois, but Rawitz
stated nothing about it.
I was much interested by the asymmetrical development of thismuscle; namely it is very massive on the right side, but much poorer,
though dilated considerably, on the left side. It must have some intimate
relation with the asymmetry of the skull and nasal passage of this whale.
( 3 ) M. ·ARY'.rAENOIDEus TRANSVERsus: (figs. 6', 7') This muscle, connecting
transversely the arytenoid cartilages of both sides, is well developed. Its
lowermost fibres insert to the cranial border of the cricoid cartilage.

On the Cetacean Larynx

35

The caudal boundary of this muscle is distinct against the upper fibres ofm. cricoarytaenoideus dorsalis, the latter covering the former to someextent. This fact coincides well with Dubois' description on B. physalus.
As mentioned· already, the cricoidal insertion of m. arytaenoideus transversus
is also present in the Sei whale : This reJation, which ·according to· Fiirbringer (1875) never exists in the human larynx, seems to occur inthe whales not rarely.·( 4 ) M. CRICOARYTAENOIDEUS LATERALIS : This muscle was described by
Stannius in Phocaena, by Murie in. Globicephalus melas and by Benham
But Meckel .and Furbringer denied the existence of it inin Cogia.
Delphirtus delphis. .Watson and Young did not mention this muscle in
Beluga leucas (cited from Dub~is). Denying its existence in Hyperoodon
and in. other toothed whales, Dubois said that the so-called m. cricoarytaenoideus lateralis described by Stannius and Murie is nothing but a ceratal
portion of the cricoarytaenoideus dorsalis. In the Sperm whaie I too can
not find this muscle.
I want to mention here my finding of a: probably new muscle, whicharises from the INNER surface of the body of the cricoid cartilage· apd
inserts to the INNER surface of ·the arytenoid cartilage (fig. 9'); Though
its attachments to the cartilages are not very firm. compared with· othermuscles, it is certainly a special muscle clearly discernible from the· surroundings. Its nature. cannot be determined at present; but the fact itself
is interesting that such an unusual cricoarytenoid muscle exists, deserving
the name, " m. cricoarytaenoideus internus ". Moreover there are several
muscular fibres scattered on the inner surface of the thyroid. cartilage, andI wondered whether the muscle above mentioned would be nothing but acollection of these fibres.. But this assumption is not very probable, for theinternal cricoarytenoid muscle is a bundle so distinctly isolated.
( 5) M. TIIYREOARYTAEEOIDEUS: (figs. 7', 8') This is a massive muscularbundle, which .arises from aµ area along the caudal notch of the thyroid
cartilage and inser~s to. the ventral and lateral surface · of the ·mtiscular
process of the aryten0,id cartilage. As to k>cality and form, this muscle
is not so unusual as in .the Sei whale, for the laryngeal sack is absent
in this whale.
( 6 ) M. TIIYREOEPIGLOTT1cus and M. ARYEPIGLOTT1cus:
Though Rawitz
denied the existence of these muscles in Phocaena commurtis, Benham

36

Hiroshi Hosokawa

found them in Cogia. In the Sperm· whale I see no muscle fibres, which
may deserve the names. The upper portion of the m. thyreoarytaenoideus
comes in contact with the p~tiolus epiglottidis, but shows no direct connection to this. Absence of these muscles might be explained from the very
. firm ligamentous c6nnection between epiglottis and thyroid cartilage, where
almost .no mobility seems to remain.
III. The laryngeal cavity
Sei whale:
The larynx of the Sei whale does not exhibit a tubal structure as in
the toothed whales. As shown in fig. 10, the aditus laryngis of the Sei
whale differs in its general form not much from that of tli.e human being.
Namely, the tongue-shaped epiglottis projects from the ventral surface ofthe pharyngeal cavity, with its apex directed somewhat upwards (about 12
cm high). From its lateral ridge on each side a fold of mucous membrane(plica aryepiglottica) js stretched, encircling the laryngeal aperture, dorsallyand downwards to· the arytenoid cartilage. The cranial processes of thearytenoid cartilages are connected between both sides by a part of mucous
membrane ; the apex, though projecting upwards a little, is situated much
lower than that of the epiglottis..
The laryngeal cavity ·is in this whale a relatively narrow space surrounded by the paired arytenoid cartilages and the single crieoid cartilage
behind. The mucous membrane, covering the inner surface, is generallysmooth, but has a few fine grooves. This cavity passes downwards behindthe caudal processes of the arytenoid cartilages, which are also connected
between both sides, and continues further with the tracheal cavity.
The laryngeal sack (figs. 11, 13-17, 18):
As related before, the laryngeal cavity has in the Sei whale a large
sack-formed appendage, which is to be named "saccus laryngis ventralis ".
It is on the ventral wall of the larynx, elongated downwards throughthe whole length of the trachea, the ventral clefts of cricotracheal cartilages
offering a space just fitted for this sack. The constituents of the thickmuscular wall of this sack were already mentioned in the precedent chapter.
The cavity within the sack is elongated longitudinally and communicateswith the proper cavum laryngis through a slit along nearly the whole lengthOn the Cetacean Larynx

37of the arytenoid cartilage. The inner surface of the sack has much folds
and grooves; as shown in fig. 11: There are many longitudinal folds inthe upper part, while the lower parts show many reticulated grooves andthe meshes are especially fine on the dorsal wall. We see many granularprominences here on the mucous membrane. In the ventral parts the folds'and grooves are considerably rough. Judging from this structure, it seems
doubtless that this sack is liable to extension and contraction in the living
whale.
It is naturally important to know the function of this highly contractile laryngeal sack. I will consider this problem at first historically.
The honour of the discovery of the laryngeal sack is ascribed to J.
Hunter, as this great anatomist stated in his study· on Balaenoptera rostrata, that a sack is present on the ventral surface of the larynx.
Since then the 'laryngeal sack has been observed by Eschricht andReinhardt (1866) in Balaena mysticetus and by Carte and Macalister, andBenham in Balaenoptera rostrata. Beauregard and Boulart (1882), who
examined the laryngeal sack in Balaenoptera musculus, B. physalus andBalaena antipodum, noticed · the difference that the sack in question is far
smaller in Bqlaenidae than in Balaenopteridae.
In the Sei whale Schulte(1916) touched this sack briefly.
The. fact that this laryngeal sack is present only in the whalebone
whales, was indicated for the first time by Eschricht and Reinhardt.
Dubois, comparing between B. physalus and several kinds of toothed whales,· ascertained this. Rawitz, too, mentioned this fact, when he studied thelarynx of Phocaena communis.
In: the meantime the problems, what is the anatomical nature of thelaryngeal sack and why this. sack exists only in the whalebone whales,
have been very differently answered. Dubois regarded this sack. ashomologous with the Morgagni' s ventricle. He came to this opinion byI
comparing the laryngeal structure of toothed whales, because these animals
have no laryngeal sack on the ventral wall of the larynx, but have a recess
on each side of the median longitudinal membranous fold ; and he explained
this recess as corresponding to the Morgagni's vent~icle. Dubois thoughtthat the laryngeal sack of whalebone whales is formed by the further
enlargement of the recess, extension of its walls and by development of
the thyreoarytenoid muscle.

Hiroshi Hosokawa

38'

But Benham doubted the homogeneity of the laryngeal sack of whalebone whales with the laryngeal recess of toothed whales, though he accepted
the correspondence of the recess with ·the Morgagni's ventricle. Such aproblem is very difficult to decide, for the two structures, both of which
are appendages of the laryngeal cavity, differ very much from each otherespecially in their relation to muscles and cartilages. On the other hand,
there are undeniable communities between them, in spite of the differencesin size, form and structure of the walls.
A key for settling the problem may probably lie in the fact, that thelaryngeal sack for Balaenidae and Megapteridae is not so large as that of
Balaenopteridae, showing, so to speak, an intermediate form between thelaryngeal recess and the laryngeal sack. · I myself ascertained the· smallnessof the laryngeal sack in a f etus of Megaptera nodosa.
Now, on the function of the laryngeal s3.ck there seem to be threepossibilities as follows.
First, it may be possible that this is an apparatus for preventing theentrance of water and food into the respiratory canal, as the contraction ofmassive muscles of this sack will make the laryngeal sack, at the sametime the larynx itself firm ?nd solid, so as to avoid mis-swallowing of alarge quantity of food with water into the larynx and trachea. Rawitz, forinstance, stated this opinion. Prof. Ogawa has also an opinion near but alittle different to this, for he thinks that the blow of air produced by contraction of the laryngeal sack will prevent the entrance of water and foodinto the respiratory canal.
The second possibility is, that this sack may concern with complete
utilization of oxygen in the inspired air. Schulte said in his paper on a
fetus of the Sei whale, " that by its contraction and relaxation. during
submergence, a circulation of air in the wide trachea and bronchi might
be set up, which would favor the absorption of oxygen by bringing the air'in these passages more rapidly into contact with the respiratory membranethan could be done by the usual diffusion currents ". Another very interesting opinion related to the second possibility was stated by Negus in his
book titled ;, The Mechanism of the Larynx'', that all the air-sacs communi~cated with the respiratory canal of animals must be for the " rebreathingof air". To explain the "rebreathing of air'', he took up the frog as an
example, saying " a frog kept under water for a prolonged period expels airJOn the Cetacean Larynx

39

from its lungs into its mouth and pharynx ; the used-up air which has beenin contact with the pulmonary epithelium mixes with the relatively unused
air which has lain in· the centre of the sac-like lungs: This mixed air,when blown back into the lungs, gives up a fresh supply of oxygen andtakes up CO,, so that respiration can be continued for a time without the
intake of· a fresh supply of air ". According to him, the laryngeal air sacs
not only of the aquatic· animals including sea-lion, whales etc., but also of
the terrestrial animals are for this purpose.
The third possibility is the relation of this sack with the phonation.
The Sei whale has no vocal cord in the larynx; its absence is also provedin other whalebone and toothed whales.
And so, it is generally believedthat the whales produce no voice. Some !iUthors however insisted upon
voices of whales (Schneider, 1795; Murie; Rawitz). Turner (1872) explained
the mechanism of phonation in Balaenidae as such, that the elongated caudal, processes of the arytenoid cartilages are drawn near to each other andvibrate by the strong exspiration of whales. This opinion was accepted byWeber and Dubois, and was, though denied by Rawitz, adopted again byGoppert in .f!olk's "Handbuch der vergleichenden Anatomie" (1937). If
such a mechanism of phonation be true, we must hold in mind the utilityof the laryngeal sack in this function.
At pre~ent it is impossible to determine, which of these tqree be thefact. Moreover the truth may lie outside of them.
· Relation· of the laryngeal sack with ·th.e internal structure of the brain(fig..19):
While the Sei whale has a large laryngeal sack, the Sperm whale has
not such a sack. Probably relating to this difference, a remarkable different
structure was found in the medulla oblongata of whales. Namely, thenucleus ambiguus is poorly developed in the pigmy Sperm whale, Cogia
breviceps.(Fig. 12'), while the same nucleus shows in the Sei whale such a
striking development that the name ''a,mbiguus " is very unsuitable for thisanimal. Prof. Ogawa (1948) has directed his attention for the first time tothis fact and ascribed the· e:xtraordinary ·development of this nucleus in the Sei
whale to the large laryngeal sack. For the massive muscular sheets of thissack are innervated by the vagus and it is generally believed that thenerves innervating laryngeal muscles arise from.the nucleus ambiguus.

40

Hiroshi Hosokawa

To make this problem more definite, we must examine in the future
the brains of Megapteridae and Balaenidae, for the laryngeal sack of themis, as already mentioned, much smaller than that of Balaenopteridae, butlarger than the laryngeal recess of toothed whales.
Sperm whale :· The entrance to the larynx is in this whale a transverse fissure at the
top of the aryteno-epiglottideal tube, which protrudes into the choana andis encircled at its neck by circular fibres of the palatopharyngeal muscle.
The larynx of the Sperm whale shows therefore the well known characteristic of various toothed whales (figs. 7', 10').
Figure 11' shows the inner surface of the· laryngeal cavity. In thissketch the whole· larynx except the epiglottic cartilage is cut in the medianplane and the right half is removed. The cavity communicates above withnasal. cavity through the laryngeal aperture and below · with the tracheal
canal, while the greater part of this cavity belongs to the aryteno-epiglottideal. tube. Along the median line of the ventral wall, we see· a longitudinalelevation covering the median crest of the epiglottic cartilage. The mucous
membrane of the laryngeal cavity has numerous fine furrows and folds.
Very fine furrows run longitudinally in the upper half of this cavity andbetween them many minute points or holes are seen in rows. The mucous
membrane,· which covers the medial surface of the arytenoid ·cartilage isquite smooth, lacking of furrows. In the lower parts, near the trachea,
there are fine reticular furrows and folds, while the part covering themedian crest of the arytenoid cartilage has oblique or looped furrows.
From the caudal end of the median crest a membranous fold (plica
mediana) runs to the cranial and ventral border of the cricoid cartilage
and we see here a triangular recess on each side of this fold. The furrows
are reltively rough in this part and many lacunae are present, which seemto .be aperture? of the lymphatic nodules.*This triangular recess was already refered to in relation to the laryngeal sack. The opinion that this recess would correspond to Morgagni'sventricle in other mammals was stated for the first time by Murie in his* The inner surface of the laryngeal sack of the Sei whale does not show such lacunae, but
I found many relatively larger lacunae on the ventral surface of the membrane connecting theupper ends of the qanial processes of the arytenGid cartilages of both sides. (fig. 12)

On the Cetacean Larynx

41

paper on Globicephalus melas. Watson and Young published the same
opinion for Beluga leucas (cited from Dubois) and Dubois also accepted it .
. Physiological meaning of the aryteno-epiglottideal tube : .
The opinion has been prevalent, that the toothed whales can swallow
and respirate at the same time owing to this peculiar structure, for .thealimentary and the respiratory canal can be in this way completely separated from each other. This opinion seems to have its origin in Camper(1820), and was supported by Milne-Edward (1860), Gegenbaur (1891),
Zuckerkandl (1898) (cited from Boenninghaus) and Negus (1928). But it
had not so definite basis and was opposed to by Boenninghaus fromanatomical and physiological reasons. According to him, all the mammals
must dilate its pharynx at deglutition and simultaneously the larynx must
be shut off as a reflex by contraction of the laryngeal muscles. My observations upon the larynx of the Sperm whale justify more the opinion of
Boenninghaus. I want to suggest, that, when the palatopharyngeal muscle
is contracted at deglutition to avert the entrance of food and. water into
the choana, the laryngeal aperture also must be closed, so there would
occur no respiratory action. Besides, I. suppose, the Sperm whale would
have no need to be able to swallow and respirate at the same time, because
this whale used to take its food in the depth of sea. Taking in mind thehigh pressure of water there, it seems very probable that such a tubal
apparatus is exclusively to avoid the mis-swallowing of food and water into
choana and larynx, rather than to swallow and respirate simultaneously~
Another somewhat different .opinion was offered by Huber (1934), whostated in his paper on the nasal passage of Tursiops, that the palatopharyngeal muscle around the aryteno-epiglottideal tube, together with. them. maxillonasolabialis around the blow-hole and the· muscular plug in theosseous nasal passage, . belongs to the blow-hole mechanism, which performs
the task to shut the nasal passage closely, so as to avoid the entrance ofwater into lungs, when the whale submerges into the depth of sea. At
any rate, it. is quite reasonable, also from the stan'dpoint of dynamics, toclose the laryngeal aperture by contractlng the neck of this tube by thepalato-pharyngeal muscle.
As an appendix to this work I wish to say briefly about the Phonation

42

Hiroshi Hosokawa

of Whales.
Neither the Sperm whale nor the Sei whale has the vocal cord in thelarynx. Absence of the vocal cord in whales has been written by many
authors, for· instance. by Meckel for Delphinus and Phocaena, by Cuvier,
Stannius, Milne-Edward etc. for various kinds of whales, and Hunter insisted
that the whales do not possess the ability of crying. But Schneider stated,
in opposite to Hunter, that he heard from a "Gronlandfahrer " about cryingof whales and· Murie said in his paper on Grampus rissoanus, " that somespecies of whales utter sound is now unquestioned, notably the species
under consideration and the ca'ing whale '(Globicephalus melas) ".
How can the whale then make sound without the vocal cord ? Murie
thought, taking the membranous folds above mentioned- two folds are said
to exist in the larynx of Grampus- as the substitute for the vocai cord,that the forcible blow or exspiration of the whale would vibrate these folds,
producing sound. He added furthermore that in some animals, for instance,
Hyomoschus . aquaticus and ·Saiga tartaria, the vocal cords are placednearly vertically on the sides of the larynx, similarly as in the cetacean
larynx.
Concerning the whalebone wha!es, Milne~Edward (1876) said that theywould be dumb, but· Turner, Watson, 'Young and Dubois accepted the· possibility of them to make sound. They explained that the caudal processof the arytenoid cartilage would be vibrated by the exblows of the whale,
producing thus voices. Dubois added furthermore that perhaps a similar
modus of phona:tion is possible also for Otaria gillespii. Though Rawitz mentioned, opposing to Turner etc., that it is impossible for a cartilaginous
substance to vibrate and produce voice, yet he believed the ability of
whales to make voice, especially of Megaptera boops. According to him,
the organ of phonation is in the whales not the arytenoid cartilage but
membranous folds formed temporarily in the . larynx or in the soft palate,especially during ·the rutting season.
So far I have rev:iewed the opinions and possibilities published byvarious authors on the phon·ation of whales, but, regret to say, that the
final s'3lution of this problem is far b3y.::n1 us. But it s~~ms doubtlessthat some dolphins can make sound, ·though it might be faint. Of thewhalebone whales I have not b~en told by any whaler that he heard thevoice of whales. During my Antarctic whaling trip (1917-1948), I had noOn the Cetacean Larynx

43

opportunity to experience the voice of whales. Even, when· they were
hurted by the harpoon, they did not cry at all. If they could produce
voice, I supposed, judging from the situation, that they would make voices
in such cases. Of course it is not impossible that the whales produce
sound and communicate between them especially during the rutting season.
"'
Even at that time the sound might be so faint that it does not deserve ·tobe called "voice " ; but it would be sufficient for the commun!ction
between them ; the vibration will be propagated in the water and received
by their sensitive· auditory organs. If so, there is no need for us to seek
for any special vocal organ in the larynx, for such a vibration could bep;roduced without the vocal cord from other parts of the body. At · any
rate it would be necessary to know the nature of the voice of whales, its
relation to the breeding season and so forth.
IV. Comparison of thelarynx between the.Sei and the Sperm whale
From the foregoing description I will point out the remarkable diff erences in the larynx of the Sei' and th<: Sperm whale.
-·

----

Thyroid cartilage·~---

Sei whale

Sperm whale

Relatively small, without the ·median angle.

Of a large size, with a remarkable. median angle.
·-

Epiglottic cartilage

Arytenoid cartilages

Well developed and elongated'upwards. 'Relatively small.
Caudal process is well developed· and its apex is connectedwith that of the. other side.

Cranial process is continuous
between both sides at the upper
end. The caudal process isabsent.

Cr\coid cartilagea~d

Ventral half is widely lacking
continuous downwards tothe tracheal cartilages.

Completely ring-formed.

Tracheal cartilages

Ventrallacking.

Completely ring-shaped.

parts

are

widely·-·-·Thyreoarytenoid muscle

Long ana. wide, forming thewalls of the laryngeal sack.

An ordinary muscle bundle.

Laryngeal sackOf very large size.

Lacking, but provided: with asmall recess on each side. ·Aryteno·epiglottideal tube

Lacking perfectly.

Well developed, typical forthe toothed whales.

Asymmetry of thelaryngeal structure

Almost symmetrical.

Somewhat asymmefrical (fo~example, development of m.
cricoarytaenoideus dorsalis); ·44Hiroshi .Hoso.kawa

From this table, it m,ay be concluded that the most important difference
lies in the remarkable development of the laryngeal sack of the Sei whale
and in the. typical aryteno-epiglottideal tube in the Sperm whale; For,almost all of other differen~es are mor~ or less in relation to these features,
which are at the same time·the characteristic respectively of the whaleboneand of the toothed whales.
As the last problem, I wish to consider, why such a tubal structure of
the larynx exists only in· the toothed whales? And why is the laryngeal
sack present only in the whalebone whales? These problems, I suppose,cannot be answered merely froin the functional standpoint, but areconcerned in a high degree also with the phylogenetic relation. In otherwords such remarkable differences in the lq.rynx between toothed andwhalebone whales is not to be explained solely as· acquired characteristics
during the aquatic life.
The interrelationship. between these two groups of whales does not seemto be so close, and the resemblance of their external form might be rather
explained as a convergence of organisms ; . for, the inner structures of themare, in some points, too much different to be regarded as intimately related.
Concerning_the relationship between the toothed and the whalebone whales,
Dubois remarked that " der Larynx der Odontoceti steht dem urspriinglichen Typen naher, wahrend derjenige der Mystacoceti sich weiter
entfemt hat". Rawitz opposed to this opi,nion and said, "<lass Odontound Mystacoceten-larynx sich nicht aus einander entwickelt haben konnen,<lass der erstere nicht die Vorstufe des letzteren darstellt, <lass aber
Und daraus folgt, <lass sie
das umgekehrte Verhaltnis nicht statthat.
aber an der Wurzel nicht einander zusammenhangen, nicht direkter Verwandtschaft mit einander stehen ", and I myself agree with Rawitz's
opinion. Putter (1902) also stated approximate ideas in his comparative
anatomical work upon the eyes of marine m?-mmals.
Summary and Conclusions
1) As to the laryngeal cartilages and muscles. many remarkable differences.. are found between the Sei and the Sperm whale.
2) The· larynx of the Sei whale shows the mo3t noteworthy characteristic
in the presence of an enormous muscular sack on its ventral side, saccus
laryngis ventralis, and almost all of the peculiarities of its cartilages andOn the Cetacean Larynx

45

muscles are more or less concerned with this laryngeal sack.
3) Four muscle-groups (A, B, C, D) were classified in the muscular wallsof the laryngeal Stick, with considerations upon their homogeneity withthe laryngeal muscles of other mammals.
4) These muscle-groups of the laryngeal sack are all innervated by thecaudal laryngeal nerve.
5) The extraordinarily well developed nucleus ambiguus in the medulla
oblongata of the Sei whale. seems to be intimately related with the actionof this laryngeal sack, which is probably able to contract and dilate ina considerable degree. The corresponding nucleus is not well .developedin the toothed whales, which lack of ·the laryngeal sack.
6) The general characteristic of the larynx of the toothed whales, including
the Sperm whale, lies in the upward elongated epiglottis and arytenoid
cartilage, which form altogether the aryteno-epiglottideal tube.
7) Som.e asymmetrical relations were noticed in the larynx of the Spermwhale, for instance in the development of the dorsal cricoarytenoid muscle
and in the relative position of oesophagus to , the· larynx. These asymmetries niay be related with the extraordinarily asymmetrical nasal passages of this whale.
8) With the completely ring-formed cricoid and tracheal . cartilages, theSperm whale is, together with Cogia and· Tursiops, an exceptional casein the realm of Odontoceti, for these cartilages have a median cleft inthe ventral portion in almost all of the toothed whales.
9) The lateral cricoarytenoid m.uscle was not found at all in the Spermwhale, but I saw a muscle bundle, probably not yet known, deserving
the name " m. cricoarytaenoideus intern us ".
10) The remarkable differences in the larynx between the 'whalebone andtoothed whales cannot be e:xplained merely from the adaptation of thesewhale to the aquatic life, but must be rather refered to the phylogenetic
relation ; namely, I believe, coincidently with some previous authors, thatthe two groups of whales, whaebone and ·toothed whales, are not so
intimately kindred to each other as genera1ly assumed.

Hiroshi Hosokawa

46

Explanation of figures :Sei whale
Fig. 1,Thyroid cartilage

Fig. 2,

Epiglottic cartilage

Fig. 3,

Cricoid and tracheal cartilages

Fig. 4,

Arytenoid cartilage

Fig. 5;

Larynx (ventral view)Fig. 6,

Larynx (dorsal view)Fig. 7,

Larynx. (dorsolateral view)Fig. 8,Larynx (the ventral ~ight quarter is removed)

Fig. 9,Median section through the larynx

Fig. 10,

Laryngeal aperture

Fig. 11,

Laryngeal sack (inner surface)Fig. 12,

Lymphatic lacunae on the ventral surface of the membrane connecting the cranial

Fig. 13,

Horizontal section through the larynx (1)Fig. 14,

Horizontal section through the larynx (2)processes of the arytenoid c.artilages

Fig. 15,

Horizontal section through the larynx (3)Fig. 16,

Horizontal section through the larynx (4)Fig. 17,

Horizontal section through the larynx (5)Fig. 18,

Innervation of the laryngeal muscles

Fig. 19,

Nucleus ambiguus

Sperm whale. Fig. 1'
Fig.

'

21;

Thyroid cartilage
Epiglottic cartilage

Fig. 3',Fig. 41

Cricoid cartilage

Fig. 5',

Tracheal cartilages

Fig. 6',
Fig. 7',

Larynx (dorsal view)'

Arytenoid cartilage

Larynx (dorsolateral view).

Fig. 8',Fig. 9',M. cricoarytaenoideus internus

Fig. 101,
Fig. 11',

Laryngeal aperture
Laryngeal cavity

Fig. 121,

Nucleus ambiguus of the pigmy Sperm whale (Cogia breviceps)

Larynx (lateral view, the right lamina of the thyroid cartilage is removed)On tp.e Cetacean Larynx

47· Literature. cited· l) . Tyson,E.;

Phocaena, or the anatpmy of a porpess, dis!Jected at Gresham eollege etc. London.

1680. (cited from Rawit~)2) Hunter, J.; Observations on the structure and oeconomy of whale~. Phi!os. Transact. Roy.
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Schneider, J. G.; Beitrage zur Naturgeschichte der Walfischarten. Leipzig. 1795.

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Proc.

ZooL Soc. London. 1867. pp. 477-.-482.
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118-138.
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(cited from Dubois)18) Murie, ].; On the Organisation of the Chaing whale (Globicephalus melas). Transact. Zoo!.
Soc. London. 1874. Vol. 8. p. 236. (cited from Dubois)19) Milne-Edwards, H.; Les:ons sur la physiologie et l'anatomie comparee de l'homme et desanimaux. Tome 2. Paris. 1876.
20) Flirbringer, M.; Beitrage zur Kenntnis der Kehlkopfmuskulatur. Jena. 1879.
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de Lincei Mem. Cl. Sc. fis. ecc. Ser. 3. Vol. 9. 1879. p. 160. (cited from Dubois)
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Edinburgh. Vol. 29. Part 1. 1878-79. (cited from Dubois)

Hiroshi Hosokawa

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Anat. Physiol. Vol. 14. 18'/9. pp. 467---:-474.
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Internat. Monatsschrift fiir Anat. u. Physiol. Bd; 17. 1900. pp. 245-354.
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Zoo!. Soc. London. 1901. I.. pp. 286-·300.
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Der Rachen von Phocaena communis, Less. Zoo!. Jahrbiicher. Bd. 17.

1902 (1903). pp. 1-98.
30) Putter, A.; Die Augen der Wassersaugethiere. Zoo!. Jahrb. Bd. 17. 1902 (1903). pp. 99-392.
31) Schulte, H. w. von; Anatomy of a fetus of• Balaenoptera borealis. Memoirs of the American

Museum of National History. New Series. Vol.. 1. Part 6. New York. 1916. pp. 389-502.
32) Negus,; The mechanism of the larynx. London and Tombridge. 1928.
33) Huber, E.;

Anatomical notes on Pinnipedia and Cetacea. Contributions to Palaeontology
IV. Carnegie Institution of Was~ington, Publica~ions. No. 447~ 1934. pp. 106---136.

34) Bolk und Lubosch; Handbuch der vergleichenden Anatomie der Wirbeltiere. Bd. 3. Kehlkopf.

(by Goppert). 1937.

i

49

On the Cetacean Larynx

Fig. 1.

Cart. thyreoides (1/8)

ventral viewM. thyreohyoideus~

dorsal view

Incisura thyreoidea cranialis
Cornu
hyoideumM. thyreopharyngicus

A

Incisura thyreoidea caud.

cCornu cricoideum ---Fig. 2. Cartilago epiglottidis (1/4)
dorsal viewlateral view

~ '\

I ..

!)
~
Fig. 3.

Cart. cricoides et Cartt. tracheales(1/8) dorso-lateral viewM. cricoaryt; dorsalis- - Facies artic. arytaenoidea//

A (M. thyreoaryt.)
Fades artic. thyreoidea

Petiolus epiglottidis

M. cricothyreoideus

Proc. lateralis
M. cricopharyngicus

Cartt. tracheales

50

Hiroshi Hosokawa

Fig. 4.

Cart. arytaenoides (dextra)(1/8)

dorsal view

ventro-lateral view

medial viewProc. cranialis
M. arytaenoid.
transversusD(M. aryepiglotticus)·M. cricoaryt.. "dorsalisc·,--·-··- M. cricoaryt.
'\l'll"'ll·.-..._
dorsalis(M. vocalis)A(M. thyreoarytaenoid.)

Fades articularis cricoidea

B(M. cricoaryt.
!at.)Proc. caudalis

Fig. 5.

Larynxventral view

(1/6)

M. thyreohyoideus.. - M. sternothyreoideus___ M. thyreopharyngicus

Fig. 17

Fig. 16

M. cricoaryt. dors. _-Fig. 14\ __ - - -· M. cricothyreoideus- - -A/+----Fig. 13/

Fig. 13---;,/(M. cricoaryt. lateralis)(M. thyreoarytaenoideus)

Trachea

Saccus laryngis

On the Cetacean Larynx

Fig. 6.

Larynxdorsal view (2/15)

Raphe pharyngis

Oesophagus

Fig. 7.

LarynxOesophagus,M. cricopharyngicus

M. cricopharyngicus

dorso-lateral view (2/15) -51

Hiroshi Hosokawa

52
Fig. 8.

Larynx(the ventral right quarter is removed) (2/15)

Plica aryepiglottica

Cart. epiglottidis (Petiolus)

Cart. thyreoides

C (M. vocalis)

TracheaFig. 9.

Saccus laryngis

Median section through the larynx (1/8'
Cart. epiglottidis

Cart. thyreoides

c

'

I

'

'

I

Oesophagus Trachea Saccus laryngis.
· On the Cetacean Larynx

Fig. 10,53

Aditus laryngis (1/6)

Fig. 11. Saccus laryngis
inner surface (1/6)- - Cavum laryrigis

Fig. 12.
Lymphatic lacunae on the ventral
surface of the membrane connecting the
cranial processes of the arytaenoid carttiages (1/4)

Hiroshi Hosokawa

54

Horizontal section through the Iarynx.
(1) (2/9)

Fig. 13.

~esophagus

A (M. thyreoarytaenoideus)Fig. 14.

C Horizontal section t hrough the larynx (2)
avum
Oe h
(2/9)
~~s a· M. cricopha·
Cart. arytaenoides ' ' laryngis
ryngicusM·\. cncoarytaenoid. dors
I.

- Cornu cricoideum(Cart. thyreoid.)

B
I'

Saccus 1a'ryngisAOn the Cetacean Larynx

Fig. 15.
Cavum laryngis

55

Horizontal section through the larynx (3) (2/9)
Oesophagus

M. cricothyreoideus\\

Cart. thyreoides

Fig. 16. .
Cavum laryngis

Saccus laryngis

Horizontal section through the larynx (4) (2/9)

Oesophagus

M. arytaenoideus
transversus Cart. arytaenoides
/

/

/

M.

thyreopharyngicus"".l::::,..l'--:~,

S~ccus laryngis

56

Hiroshi Hosokawa
Horizontal section through the larynx (5) (2/9)

Fig. 17.

\\'

Plica aryepiglottica

Cart. thyreoidesD- (M. aryepiglotticus)

Innervation of the laryngeal muscles (2/15)
Fig. 18.
N. vagus-N. laryngicus cranialis (Ramus extenus)

M. thyreopharyngicus -·M. cricopharyngicus- -M, ceratocricoaryt. --- ·K
dorsalis
.·•

,.,
/

M. cricothyreoideus•/' ' Saccus laryngis
N. laryngicus caudalis

On the Cetacean Larynx

Fig. 19.

Medulla oblongata of the Sei-whale (5/2)

X

Fasciculus solitarius'

57

Fasciculus longi- Nd. n.
Nd. dorsalis
tudinalis medialis hypoglossi
n. vagi

:xn

\

lX

Corpusrestiforme

-

'\

/'/

Radix n.--/glossopharyngici
1
Radix n. vagi

I

1

I

Nd. ambiguus\ Tractus, spinalis
n. trigemini/

Fasciculi
Nd. olivae Nd.
Ne!. Nd. tract. spinalis
pyramidici accessorius olivae ambiguus n. trigemini
medialis
Fig. l'b Cartilage thyreoides (Lamina dextra) (1/8)
outer surface

Fig. l 1aM. thyreohyoideus- .... - ... Foramen

Cartilago thyreoides (Physetercatodon) seen from the ventroIateral side (1/8)
Incisura ~.thyreoidea cranialis

thyreoideum,
M. sterno- i!
thyreoideus

inner surface.

M. thyreopharyngicus
J

Epiglottis, -......

Incisura thyreoidea caudalis
M. thyreoarytaenoide us' '- - - - -M. ceratocricoarytaenoid.
dorsalisHiroshi Hosokawa

58

Fig. 21a Cartilago epiglottidis (1/6)
ventro-lateral view · dorso-lateral viewFig. 21b Cartilago epiglottidis (I/6)
lateral view .
horizontal section

Syndesmosis withthe thyroid cartilage
Fig. 31
dorso-lateral view

Cart. cricoides (I/G)
ventro-lateral viewM. cricoarytaenoideus internus

Proc. cranialis

Proc. cranialis - - - - - - -M. arytaenoideus transversus - - - - - - -.....

M. cricoaryt. dorsalis - - - - -,f;.L-.,
M. crycoaryt. internus ---- -/r - - M: thyreoarytaenoideus'

Facies artic. cricoidea

59

On the ·Cetacean Larynx

Fig. 4'bCart. arytaenoides .(sinistra) (2) (1/6)

lateral view

medial viewFig. 51a. Cartilagines
tracheales (1) (1/6)
ventro-lateral view

' - - - - - M. arytaenoideus transv. - - - -\
I
I

t'

',

·-- -M. cricoaryt. dorsalis

dorsolateral view

-J

Facies artic. cricoidea
M. crycoaryt. internus - -Cart. trachealis I'---M. thyreoarytaenoideus

Fig. 5'b Carttilagines tracheales (2) (1/6)
median section
Fig. 61 Larynx (2/9)
ventral -dorsal viewM. thyreoary- Cart. ary- Cart. epi- M. arytaen.
taenoideus
taenoides
glottidis transversus
/

/

/
/

/

.
M. ceratocricoarytaen. dorsalis

Hiroshi Hosokawa

60

Fig. 7'

Larynx (2/9)
Aditus laryngis

Cartilago arytaenoides

Tuba aryepiglottica

Cartilago thyreoides- Cartilago
thyreoides(Lamina
dextra)- - - M. thyreoarytaenoideus

Cartilago
cricoides.

M. cerato- ___ ,,cricoarytaenoideus
dorsalis/,

Fig. 8'Larynx (1/6)- - .,. Aditus laryngis- - -- Tuba aryepiglottica

Cart. cricoides __ _Cartilago
thyreoides(Laminasinistra)

//
.c.-/

M. cricoaryt.
dorsalis
I

I

Fades articularis thyreoidea

M. thyreoarytaenoideus

On the Cetacean Larynx
Fig. 9'.61

M. cricoarytaenoideus internus (1/6)
medial view
~ventralCart. arytaenoides

M. cricoaryt. internus

Cart. cricoides - - - -Fig. 10'Aditus laryngis (1/6)_____ Cavum nasi--- - - Aditus laryngis------ Tuba aryepiglottica
M. palatopharyngicus- Cavum pharyngis

Oesophagus
M. cricoarytaenoid. dorsalis
TracheaHiroshi Hosokawa

62

Fig. 111

Cavum laryngis (1/6)+

dorsalcaudalrostralventralAditus laryngis

Cartilago arytaenoides(sinistra)
M. arytaenoid. transversus ,M. cricoaryt.

Cart. cricoides -Trachea-

Cart. cricoides /1
Recessus.
M. thyreoarytaenoideus Plic~
mediana laryngis
Fig. 121 .

Cart. thyreoides

Medulla oblongata of the pigmy Sprm-whale (10/3)
X

XIl

Nd. n. hypoglossi

Fasc. longit. medialis
I

I

/

/

....

Fasciculus ------~--,
solitarius-..... --·--·--·.Nd. dorsalis
n. vagi

Corpusrestiforme- -Tract. spinalis
n. trigemini
\
\

. .
./
Rd
a rx n. vagi

/

I

\

' '·----Nd. tractus
spinalis n.
trigeminiI

Ne\. ambiguus

Nd. oli~ae acces- Nd. oliv~e Nd. ambiguus
sorius medialis