650 SIR WM. TURNER ON THE PLACENTATION OF HALICORE DUGONG. 



end was dilated into so bulbous an expansion as obviously to interfere with, the ready 

 extraction of the villus from the crypt (fig. 11). 



The substance of each villus consisted of a delicate connective tissue such as one is 

 accustomed to see in these structures. Many had a definite epithelial investment, the 

 cells of which were irregularly polygonal, but others had lost their epithelial coat. 

 What, however, was especially noticeable was the large amount of cells, either singly 

 or in groups, which were seen floating in the fluid in which the villi were examined after 

 they had been teased asunder with needles. These cells consisted in part without doubt 

 of the epithelial investment of those villi which had lost their covering probably in the 

 process of teasing ; but from the numbers seen I think that many were derived from the 

 lining epithelium of the maternal crypts, which having been detached and intermingled 

 with the villi, had come away with them when the fcetal placenta separated from the 

 maternal. 



Projecting from the inner surface of the endochorion into the allantoic sac were 

 numbers of flattened leaf-like bodies, which I shall name the allantoic bodies. They 

 were arranged either singly, or in pairs, or sometimes in rows of several situated close 

 together. They were confined in their position to the allantois close to the placental 

 borders, or to that part of the placenta which was covered by the allantois. They grew, 

 therefore, from the most vascular part of the membrane, and were continuous with. the 

 coats of the blood-vessels, more especially the veins. These allantoic bodies varied in 

 shape and size. Some were elongated and attached by narrow pedicles to the endochorion ; 

 others were broader than long, and with broad bases of attachment, and when a row of 

 them occurred close together along the course of a particular vessel they sometimes were 

 continuous with each other at the base of attachment. The longest of these bodies was 

 f of an inch, but ^ an inch (13 mm.) was a more usual size. The base of attachment 

 was in many cases f of an inch, but when two or more had fused together the base was 

 much more elongated. The smallest allantoic body which I measured was 3 to 4 mm. 

 in diameter. In colour they were light brown, like that of the allantoic membrane, 

 but this was probably not the natural tint, as the membranes were all stained and 

 discoloured. All these bodies were flattened, but this may possibly have been due in 

 part to post-mortem compression, after the allantoic and amniotic fluids had been 

 evacuated, and the weight of the foetus had pressed against them. 



Some of the allantoic bodies were then removed along with the part of the vessel 

 to which each was attached and prepared for microscopic examination, and sections 

 were made through them and their blood-vessel from the attached to the free border. 

 They were seen to be continuous with the fibrous connective tissue coat of the vein, to 

 which they were attached by the base, and in tracing them from the base to the free 

 border they became more and more attenuated. They consisted for a part of their 

 thickness of wavy bundles of white fibrous connective tissue; but in the axis of the body 

 the tissue was modified in appearance. When teased out with needles elongated fibro- 

 cells could be isolated, the characters of which were scarcely sufficiently differentiated to 



