PLATANISTA. 485 



tint. They, moreover, are distinguished from the utricular glands in possessing the 

 above-mentioned large open stellate areas or glandular receptacles. 



External appearance of the gravid uterus.— Tha left horn forms the bulk of 

 the organ and is an oval sac lying obliquely across the abdomen with the left 

 placed considerably posterior to the right pole. It measiu-es 17-75 inches in transverse 

 length, pole to pole, and its upper border is distant 19- 25 inches from the anterior 

 extremity of the vulva. The right horn depends as a globular pouch from the an- 

 terior surface of the right third of the left horn, close to its posterior border, and the 

 internal septum which separates the two horns is marked externally by a puckering 

 of the serous covering. This horn measures 12 inches antero-posteriorly and has a 

 breadth from right to left, when collapsed, of 7'50 inches. 



Cavity of uterus. — The portion below the two horns is cup-shaped, and not more 

 than 2-50 inches in length, measured from the os uteri internum to the dorsal origin of 

 the mesial septum, which indicates the lowest limit of the left horn and the opening to 

 the right horn, but its diameter from the free margin of the mesial septum to the left 

 waU of the uterine cavity is 5-50 inches. The left horn and the common cavity of the 

 uterus are thus continuous with one another. The right horn, however, occurs as a 

 diverticulum from the right side of the common cavity of the uterus, and its entrance 

 is guarded by two valvular folds of mucous membrane, one the external fold, which 

 corresponds in position to the angle formed by the bending backwards of the horn 

 upon itself, while the internal fold is the mesial septum. The former is a triangular 

 fold with its broad free margin 5-50 inches in breadth and directed forwards and out- 

 wards. It lies between the ventral and dorsal walls of its cavity, and its apex is 

 directed towards the os uteri internum. It has an extension of 3'50 inches. The mesial 

 septum, which is much thinner than the former, is du'ected inwards and backwards, in 

 which course it has a length of 5'75 inches, with a bold crescentic free border of 4-76 

 inches, arching from the anterior to the posterior walls of the termination of the 

 common cavity of the uterus. Besides assisting in shutting off the right horn from 

 the uterine cavity, the mesial septum forms the wall of the right pole of the left 

 horn. Opposite to the mesial septum and continuous with the left wall of the 

 common cavity of the uterus is another septum corres23onding to the septum of 

 the right horn, partially dividing the left horn into two. It has considerable dorso- 

 ventral extension, and its free margin, which is directed forwards and inwards, is 

 slightly concave and measures 5'50 inches in extent. Erom its free margin to the 

 os uteri internum is 5"75 inches, and on its left surface it measures 3"75 inches. The 

 appearance of the cavities when laid open is shown in fig. 1, PI. XXXIV, in which 

 the impregnated left horn is seen to bend round at its right end between its own and 

 the median septum, while the right horn is shut off by the valvular arrangement 

 just described. The entrance into it is by a canal three inches long by the same in 

 breadth, directed outwards and slightly forwards. The horn itseLP into which this 

 broad passage leads, is a little more than 6 inphes long by 4 inches in breadth a 

 little above its middle. The anterior wall of the canal is very rugose, especially its 

 aspect in the horn*, and, as was to be expected, it is double the thickness of the walls 



