A DOLPHIN (STENELLA CAERULEOALBA) WITH
PROTRUDED RUDIMENTARY HIND LIMBSSEIJI OHSUMIOn December 16 in 1963, a herd of about 450 blue white dolphins (Stenella caeruleoalba)
was caught by fishermen at Kawana Beach in the eastern coast of Izu Peninsula,
Japan. In the course of biological investigation on the herd, I found an individualwith protruded rudimentary hind limbs.
Dr. Nishiwaki and his group have investigated this species of dolphin on aboutten thousand individuals, but it is the first time for us to find such an individual.
On the protruded rudimentary hind limbs in the postnatal cetacea, there havebeen reported for one humpback whale (Megaptera novaeangliae; Andrews, 1921)
and sperm whales (Physeter catodon; Ogawa & Kamiya, 1957; Nemoto, 1963).
Slijper ( 1958) reviewed two similar records on a dolphin and a pilot whale.
Ogawa (1953) reported on the presence of the hind limbs in the embryos ofthe blue white dolphin. And he described that 14 mm long embryo had easily
observable hind limbs, keeping pace with becoming smaller of hind limbs protrusion, in 25 mm long embryo the elevation of the flukes made appearance and inlarger embryos, there remained no trace of hind limbs elevation at all.
Present individual is a male, and is 230 cm long. Body proportions are shownin Table 1. The proportions are not so different from the normal ones except only
one part. The distance between anus and reproductive opening in this dolphin isshorter than the usual. Body colour and pattern of the individual is not different
from normal individuals except the haunch portion. As shown in Plates I and II,
the margin of pigmentation at anus is different with the normal. The margin of
the insertion of the protruded hind limbs is white, and the hind limbs are black.
Furthermore, one clear black line is seen along the margin of pigmentation in theventral portion of each side. In general, there is abnormality in the haunch portion.
Weight of testes is 31.0 gr. in the left side and 29.8 gr. in the right side. In
vas deferens fluid were observed many mature sperms. Then this individual isdesided to be sexually mature.
Rudimentary hind limbs are protruded on either side of just the mammaryslit. Distance between the both tops of limbs is 101 mm. The distance between
both anterior margins is shorter than that between the posterior margins. Protruded
limbs are ellipsoid. Base of the limbs are oval. The minor axis of the left andright limbs is 22 and 23 mm respectively, and the major axis of the left and rightlimbs is 28 and 33 mm respectively. The height is 10 and 13 mm in the left andright limbs respectively.
This specimen was preserved in the Department of Anatomy, School of Medicine, University of Tokyo, and anatomical study will be made on the internal
structure of the rudimental limbs in the University.
I am much indepted to Dr. T. Kamiya of the Department of Anatomy, Univer135

136

S. OHSUMITABLE 1. MEASUREMENT OF BODY PROPORTIONS FOR THE PRESENTSPECIMEN AND THE NORMAL SPECIMENS IN THE BLUE WHITE DOLPHIN
Items
Present (cm)Normal (cm)*Total length
230.0
221-239
Length of snout
10.5-12.0
12.0
Tip of snout to blow hole29.0-36.5
32.0
angle of gape25.0-27.5
27.5
34.5
center of eye
28.0-36.0
anterior margin of flipper49.0
44.0-51.0
Notch of flukes to posterior margin of fin
96.0-106.5
106.0
Length of insertion of flukes
14.5-17.0
17.0
Notch of flukes to anus
61.0-69.0
70.0
to umbilicus
113.0-130.0
129.0
Anus to reproductive opening
15.0-21.0
13.5
Flipper, anterior margin to tip
29.0-31.5
32.0
broadest width
9.5-11.0
11.0
Fin, length of base27.0-35.0
32.0,, height
19.5
19.0-23.0
48.0-59.0
56.5
Flukes, total width*from 6 specimens (males), body lengths ranged between 221 and 239 cm.

sity of Tokyo, who kindly took photographs of the specimen and gave me somemeasurements. And I also due to Dr. M. Nishiwaki of the Whales Research Institute to give me the chance to find the present specimen.
REFERENCES
ANDREWS, R. C. (1921). A remarkable hind limbs in a humpback whale. Amer. Mus. Novitates, 9: 1-6.
NEMOTO, T. (1963). New records of sperm whales with protruded rudimentary hind limbs. Sci. Rep.
Whales Res. Inst., 17: 79-81.
OGAWA, T. (1953). On the presence and disappearance of the hind limb in the cetacean embryos. Sci.
Rep. Whales Res. Inst., 8: 127-32.
OGAWA, T. & KAMIYA, T. (1957). A case of the cachalot with protruded rudimentary hind limbs.
Sci. Rep. Whales Res. Inst., 12: 197-208.
SLIJPER, E.J. (1958). Walvissen (Translated by Pomerans, A. ]. into English. Hutchinson, London,1962, 475 p.).

PLATE I
Upper:Lower:

A blue white dolphin with protruded rudimentary hind limbs.
A normal male blue white dolpin. Ventral view.
PLATE II(Photographed by Dr. T. Kamiya)

Upper: Ventral view of the protruded rudimentary hind limbs.
Lower, left:
Sidal view of the left hind limb.
Lower, right: Sida! view of the right hind limb.

Ventral view.

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