206 Prof. J. Wood-Mason and Mr. A. Alcock. [Nov. 26, 



Sections, both transverse and longitudinal, through a trophonema 

 display a central core of fine connective tissue, in which, besides 

 arteries, veins, and a dense capillary plexus, are cells and very numer- 

 ous free leucocytes ; and surrounding or external to this a series of 

 solid finger-shaped coagula formed of confluent cells in various stages 

 of degeneration. At the one extreme, these finger-shaped masses are 

 seen to be made up of desquamated cells the protoplasm of which 

 lias simply become confluent into a solid mass wherein the nuclei, 

 with the nuclear network very clear and conspicuous, stand out 

 distinct and unchanged; while, at the other extreme, are found 

 nothing but solid granular coagula in which neither nuclei nor 

 structure of any kind can be distinguished, with leucocytes scattered 

 between them. 



We may anticipate events by stating that these solid masses of 

 cells and granular coagula appear to be "epithelial casts" of the 

 glands which, as we shall show, invest the surface of the tropho- 

 nernata in the earlier stages of pregnancy, but which, at the close of 

 pregnancy, are undergoing coagulative degeneration, while the 

 leucocytes present appear to be exercising a resorptive function. 



4. On the Uterus and Trophonemata of Trygon walga at the 

 Beginning of Pregnancy. 



The second female specimen is about the same size as the first, but 

 had not the same convexity of the abdomen. It also has the right 

 ovary and oviduct undeveloped, while the left ovary is enlarged and 

 distended with ova, and the distal end of its oviduct is dilated into a 

 pyriform uterine chamber, which, however, is smaller than in the first 

 specimen measuring only 32 mm. from the f undus to the os. An 

 egg which had recently descended into the uterus was ruptured 

 accidentally in dissection. 



The uterus has at this stage in all respects the same form as it has 

 at the end of pregnancy ; but the trophonemata, on the contrary, are 

 as strongly contrasted as possible in the two stages. For while in the 

 late stage they have the form of an elongated cone and are in process 

 of disintegration, in the early stage they are strap-shaped and are in 

 process of integration. That the trophonemata were not functioning, 

 their incompletely evolved condition proves, apart from the considera- 

 tion that in the well-filled yolk-sac there would be abundant sustenance 

 for the embryo for some time. 



The trophonemata are somewhat wavy, rather thick and fleshy, 

 strap-shaped bodies, measuring about 10'5 mm. in length by about 

 1 mm. in greatest breadth. Narrow at their origin, they almost 

 immediately widen out to their greatest breadth, which is maintained 

 to about the seventh tenth of their length, whence they taper to their 



