New-York tribune., 1872-03-28
THE HASSLER EXPEDITION.
LETTER FROM PROF. AGAssIz.

Prol Peiroe Of Harvard College from Prof. Agassz,
giving interesting details respecting some Of the results
0; the researches Of the Hasslcr Expedtonl
RIO, BOARD TIR HAssLER. Feb. II. 1872.
NJ DEAR PIERCE: On January IS, Pourtalls dredged
20 very hour during the night, the weather being
more favorable for this kind OF work than had been at
ct any previous time left Boston As did not
dare 70 remain exposed to the dew. ! missed the
most interesting part OF the proceedings about
which POurtahs will report himself The next
morning however. had an opportunity
OF overhanng the specimens brought UP by the dredge
and TO my great delight discovered among them ano
ther of those types OF past ages only found nowadays
In deep The is entirely as the speci-
men question belongs TO the Pectinids family the
relations Of which to earlier geological formations have
far presented nothing especially interesting OF IN
structve except perhaps the fact that the type OF
ueither exclusively crctaceous. wish had within
my reach the means OF making full statement OF the
ct but have not the necessary books Of reference.
and this trust entirely TO my memory.
Among the remarkable species OF Pecten, there
i A very small one. figured In Goduss under the name
NJ Pectcn paradoxus II remember rightly, and found
IN the IAas OF Germany which have always been In
rned ~ consider the type OF distinct genus on ac-
r,unt " its structural peouliares. AS yet nothing
Ike 10 has been made known among the living Shells
Now among the few specimens dredged this occasion
IN s0o fathous depth OF the mouth OF the Rio Doce
there was one living specimen of the same
I'm, a. the Pecten paradoxus, showing par
tenr.y and very distinctly the prominent radiating
rms risin- on the surface OF the shallow waive 10
,hi the fossil IL indebted for It's specuc name Like
tse fos-il the living species is Of small dimensions
rneasur.nr hardly twO-thirds Of an inch hope may
~. ahe t,ssect the animal at future time. aud
-h ant tho anatomical character of this exceptional
tyne WIN 10 a few other shells already known 10 U.s.
rom deep waters were also found; among thein' TWO
beautiful species Of PleurotOma, dentca Win species
FOUND In TlOrlda, OF DarbadoeS
In NV trst letter to YOU concerning deepsea dredg-
tne. You may have noticed the paragraph concerning
,rustacea IN which 1t is stated that among these animals
We may expect genera reminding us Of some Amphl-
pods and lsapods aping still closely the IrloDes
chan scrolls" A specimen answering fully 10 this state
ent actually been dTedged in 40 fathoms about 40
miles east of Cape FRO II Is most curious animal
At frst sight 1t looks like ordinary IsoPod, with
a broad short, fat body. Tested by the charao
tar assigned TO the leading groups Of crustacea
vhetheT we follow Min, Edwards or Danas
classification. it Can, however be referred TO no
one Of their orders families. AS have not the works
1f authors before shall have TO verify more
carefully aese hereafter. but believe can
rust NV fast Inspection The general appearance OF my
new crl,socan very Ike that Of Scrolls, with this
marked difference however that the thoracic irn Gs are
nuch more numerous and the abdomen or pygidlum Is
much smaller. 1t cannot be referred TO the
Pldopthalmarians OF Milne Edwards (Which cor
respond. 10 the Decapods Of Dana) because 1t has
neither The structure Ot the mouth nor tne gus nor lue
;r;s pedunculated Of this highest type OF
e crulcoa nor can be referred to the Teradecapods
~ Dana which embrace Milne Edwards's Amphpods
snd IscpOds) because IL has than seven pairs OF
.1Oracc umbs 1t cannot be referred to the Entomo-
--raca because the thorlcic are all provided with
locomotive appendages OF the same kind But 1t has
very striking resemblance 10 the Trlobites' 1t
"a In fact like the latter OF those types,
Oubnins the characteristic structural features OF other
ndependont groups which 1 have first distinguished
under the OF synthetic types Its resemblance 10
hr rrobites unnistakable and very striking In the
frat place the head stands out distinct from the
thoraric regions, as the buckler Of Trilobites
md the large kdney-shaped fscetted eyes re-
m those Of Calymene; moreover, there is
facial suture across the cheeks. as In Inlobites'
sothat it not for the presence OF the antenne
which project the lower side OF the anterior margin
n the bucker two unequal pairs these resemDances
would amount to absolute identity Of structure AS
it the presence o. an bypOstome, In the same position
s piece Of the mouth is found In TTo0ites renders
enc similarity TO this extinct type OF crustacea still more
striking while the antenne exhibit an unmltakabie
-esembance 10 the IsOpOds
N view Of the synthetic character OF these structural
tures IL should not be overlooked that the bucker OF
.ur new crustacean. for which propose the name Of
Tlnocaris Peircei, extends sideways into taperng
-nt curved backward the first thoracc ring az Is
the with great many TrObites The thorax con-
al. .ts Of nine rings. seven OF which have prominent
points,
OpnuA Lichas, &c The sixth ring is almost
.,poe,led between the fifth and seventh. and
- destitute Of lateral projections, is also the ninth
Theae rings are distinctly divided into three nearly
equal obos by fold bend each side Of the middle
region that the hOrax has the characteristic appear
ance NJ that Of the Trobes 70 which the latter owes
"a name The legs are very slender and resemble more
those Of the CopepOds and Ostracods than those OF any
other rusacea There nine pairs OF them all alike
IN structure six Of which, however the anterior ones,
ara larger than the three last which are
also more spproximated 10 each other. Besides the
Ie-s there "a pair OF maxillipeds attached 10 that
DEt Of the buckler which extends back OF the
fBclal suture These maxlnpeds resemble the claw Of
CyoOps AL these appendages inserted in that part
II The corresponding TO the bend Of the thoracc
Iooes that there exists real affinity between the
TrlObres and little crustaeean, and their resem-
bl1nce - simply OF analogy. ought here
after look corresponding position for the inser
aon OF the limbs Of TrloDes. do not remember with
sufficient precision what Billings, Dana and Verril
have lately published concerning the limbs Of Trlo-
Diees say now what bearing the facts described
above have the subject lately discussed In
ne Journal Of Science. But OF thing satisfied,
: have examined the TOmocaris Percei-that
Tul0bitcs not any more closely related TO the
P5ylopods than 20 any other EntomOstrace TO the
topofs In reality. the TrlObites like TOmocaris,
.yuthefie type In which structural features of the
f-trldeoapOds combined with characters of Ento-
no-tracs and other pecuarites essentially their
The pyeidum abdomen OF Tomocaris is very
Ike The abdomen OF the ordinary IsOpOds with an artcu-
l4ted oar attached sideways and lesfike respiratory
rgaBs upon under side. The whole pygdium is EN-
traced between the last curved points OF the side
y the thGrax. owing to these various cOmbina-
lons. would expect IN TrilObites phylopod-
Ike respiratory appendagos under the pygi-
hum only. and slender. articulated legs, with
brstes under the thOrax, thin and artculated
y narrow Joint easily to break of without leav-