Macalister— the Anatomy of Aonyx. 539 
XLIX. — On the Anatomy of Aonyx. By Alexander Macalister, 
M. B., Professor of Comparative Anatomy and Zoology in the Uni- 
versity of Dublin. 
[Read November 10, 1873.] 
In the valuable collection of animals collected by the late lamented 
Viceroy of India, the Right Hon. the Earl of Mayo, for the Dublin 
Zoological Gardens, was a fine specimen of the laughing otter of the 
Indus. This animal lived for a few months in the gardens, but in the 
month of August last it suddenly sickened and died, and was purchased 
for the Museum of the Dublin University by Professor Haughton. On 
examination, its conical tapering, hairclad tail, its bald soles, muzzle 
edge and columella, its oblong feet with slender free- tipped toes and im- 
perfect claws, its large pad, and separate toe-pads; its broad, de- 
depressed skull, showed that it was a member of the genus Aonyx esta- 
blished by Lesson. The index and middle toes show a tendency to unite 
to the third joint, the inner toe is short, the fifth shorter than the index; 
the skull is rather short, convex behind ; the flesh tooth has a large 
internal lobe nearly as long as the outer portion of the tooth, with two 
cross ridges on the crown ; the upper tubercular grinder is large, 
massive, rather wide than long. 
The Asiatic species of the genus Aonyx are three in number. A. 
leptonyx of the Indian Archipelago, which has pale brown cheeks, chest, 
and sides of the neck, white chin and upper part of the throat, and 
brown back; A. indigitata, which has very short toes and blunt 
rudimental claws ; and A. aureobrunnea, the small golden and brown 
otter of IN'epaul. Our specimen agrees with the descriptions of none of 
these very accurately. 
With the assistance of Mr. Mackintosh, I made a very accurate 
dissection of this animal, and the following are the details thereof. 
Pending the compilation of a general account of the anatomy of the 
musteline section of the carnivora, I have confined myself to the 
description of the species without introducing any comparison. 
The panniculus carnosus was strong, and overlay the strong laminar 
connective tissue of the neck and thorax. The following parts of it were 
recognised. 1. Platysma myoides from the inferior surface of the 
thoracic integument to the ramus of the mandible, its fibres running 
upwards and inwards, and forming a strong superficial stratum in the 
neck. A second or nuchal panniculus arose along the medial line of 
the neck from the first dorsal spine to the occiput. The fibres ran 
forwards and outwards obliquely, overlapping the trapezius to be 
inserted into the skin and connective tissue of the side of the neck. 
The occipital segment of the occipito-frontalis is a detached flat band of 
this muscle. A strong transversalis nuchsD underlay the nuchal pla- 
tysma, and ran from the middle line directly outwards to the integument 
R. I. A. PROC. — VOL. I., S1£U. IX., SCIENCE. 4 A 
