PLATANISTA. 489 



side. Tlie glands would appear to be not quite so numerous immediately below a 

 spot, but the careful observation of their distribution and of their relations to the 

 spots leads to the conclusion that, as in the sow and in the other MammaHan uteri, 

 ah-eady referred to in this work, the smooth-spots of the gravid uterus of Platanista 

 would seem to hold the same relations to the gland layer. Viewing the uterus with 

 a hand-lens I have frequently seen what appeared to be unmistakable evidence of 

 an opening of a gland, and in pm^suing the plan of dissecting off the gland layer 

 from the back of such a smooth-spot I have further convinced myself of the inti- 

 mate relation of the glands to it and of their terminating in it, but under the 

 microscope after the examination of a most extensive series of sections I have never 

 yet been able to demonstrate conclusively the opening of an utricular gland in such 

 an area, not that we ai^e to conclude that it is absent, but that the difficulty of 

 demonstrating it is great. 



Chorion. — The membranes (PI. XXXIV, fig. 2) present three well-marked por- 

 tions corresponding to the three divisions of the cavity of the womb. The first is 

 the great sac moulded to the mucous surface of the left horn ; the second is the 

 sac filling the unf ecundated right horn, and the third is what Professor E,olleston' has 

 called the csecal extremity of the membranes from the two horns, projecting into the 

 short corpus uteri. When the amnionic and allantoic fluids are drawn off", the chorion 

 contracts into numerous rugose folds, which are very strongly marked in the right horn 

 and on its uterine sac, but when the allantois is filled, and the membranes are placed 

 in water for about half an hour, all these strong folds disappear, or slight traction 

 demonstrates the fact that they are temporary. They radiate from the Eallopian 

 poles of the chorion and from the apex of the uterine sac, but they are very feebly 

 marked on the left horn, which has been greatly distended by the foetus. In its 

 distended state, however, the chorion is marked by certain persistent folds that are 

 not removed by any amount of tension. When placed in water they form wavy 

 fringes, and the most prominent run from the uterine pouch {sp) to the angle of 

 union of the two horns of the chorion. In passing on to the left horn their course 

 is interrupted by a long linear bare patch hereafter to be described, but beyond 

 this point they course round the right pole of the left horn to the dorsal aspect 

 where they are lost. Each forms a wavy fringe about half an inch in breadth 

 in its broadest part. These folds radiate from the perfectly nude space as the 

 apex of the sacculated portion of the membrane which depends into the corpus 

 uteri (PI. XXXIV fig. 2, sp. and 3,) and which corresponds to the lamellarly 

 folded OS uteri internum. This stellate bare patch (fig. 3) has a strong resem- 

 blance to the similar area in Orca and in the mare as described and figured by 

 Turner. A few persistent folds occur at the two poles of the chorion and are doubt- 

 less adapted to the folds of the Pallopian orifices. Besides these, many fine rugose 

 folds encii'cle the left horn of the chorion, and are especially numerous and best 

 marked to the right of the umbilical region, where they correspond to the folds 

 of the septum of the left horn, and in this region they spring from a Unear bald 



' Trans. Zool. Soc, Vol. V, 1866, p. 307. 



o3 



