204 
DBS. A. CAETE AND A. MACALISTEE ON THE 
from each other by a straight median sulcus, which commenced about 1 inch in front of 
the anterior commissures of the semilunar nasal outlets, and fell short of their posterior 
commissures by about the same distance, thus ^ ; it was about \ an inch in depth, and 
its use was evidently to facilitate the approximation of the lips of the nares. 
No hairs were discernible in the immediate vicinity of these outlets, as existed in the 
specimen described by Eschricht and Reinhardt; on the contrary, the skin in this 
situation was smooth and polished. 
The pudendal fissure was situated a little posterior to where the abdominal folds ter- 
minated, at a point on the ventral surface coincident with a perpendicular line let fall 
from the dorsal fin; it opened by a longitudinal slit or sulcus, which was bounded 
on each side by thick and rounded labia on the central line of the abdomen. Into this 
the orifices of the urethra, vagina, and rectum opened ; the urethra being situated most 
anteriorly, the rectum at some distance posteriorly, and between them the vagina. 
The umbilicus also lay in a small slit-like furrow, at the distance of about 6^ feet 
anterior to the fork or commissure of the tail. 
External and parallel to the pudendal fissure were two other sulci, in which the nipples 
of the mammary glands were concealed, but owing to the immaturity of the animal 
these glands were not well developed. 
The mouth and fauces were lined by mucous membrane of a pale pinkish colour, 
which was arranged in longitudinal folds similar to those on the geniothoracic region 
of the animal ; this membrane, together with the mylohyoid muscle and skin, formed 
the wall of the great submaxillary pouch, which from the elastic nature of its component 
parts, was capable of great distention ; this enabled the animal to take into its mouth 
a large quantity of water containing such substances as constituted its food ; the latter 
was retained in the mouth by the straining mechanism of the baleen plates, while the 
superfluous water was expelled by the contraction of the pouch. 
The number of baleen plates was about 280 in each upper jaw, or 560 in all. The 
longest blades were placed at the posterior third of the long axis of the jaw, and mea- 
sured 3^ inches in length on their outer border ; from this point they gradually decreased, 
both anteriorly and posteriorly, to the length of about 1 inch, finally passing into coarse 
bristles about f inch in length. Each plate was somewhat triangular in outline, and 
was attached to the jaw by its base or shortest side, which was imbedded in the basal 
pulp, and measured If inch in length. The outer margins were long and curved, their 
concavity directed outwards ; this curve was greatest at the centre and continued very 
well marked to the anterior extremity, but diminished towards the posterior end, where 
the outer margins of the plates became comparatively straight from above downwards ; 
the inner borders of the plates were fringed by bristles, which were coarse towards the 
apex of each plate, but became much shorter and finer towards the internal margin of 
the wreath. Each plate was curved transversely, the concavity being directed backwards ; 
the inner margin of each lamina, just where it came in contact with the subsidiary 
plates, had, however, a slight inclination forwards. 
