SIR WM. TURNER ON THE PLACENTATION OF HALICORE DUGONG. 645 



less abundant, and they had the appearance of fusiform, caudate, or stellate cells. 

 Divided blood-vessels were also not unfrequently met with ; sometimes they were empty 

 and contracted, at other times the lumen was occupied with red blood corpuscles ; the 

 former were presumably arteries, the latter veins. 



As regards the relations of the glands to the interglandular connective tissue, the 

 gland wall was usually separated from the surrounding tissue by an interspace (fig. 7), 

 which may, perhaps, be a lymph channel. The connective tissue bounding such an 

 interspace externally was usually a well-defined bundle arranged in a definite manner 

 around the gland-tube. 



I then proceeded to examine the placental zone of mucous membrane from which the 

 chorion had been detached. In the first place, I used only a simple lens, and with it went 

 carefully over the free surface of the zone, which had a spongy character ; for it was 

 perforated by minute orifices, many thousands in number. They were circular, sub- 

 circular, or polygonal in outline, and were closely crowded together, being separated from 

 each other by delicate bands of mucous membrane (fig. 10). These openings communicated 

 with crypt-like depressions in the maternal placenta in which the chorionic villi had been 

 lodged. The form and arrangement of these crypts was determined when vertical 

 sections through the placental zone were made and examined. Interspersed at intervals 

 amidst these minute orifices were somewhat larger openings distinctly visible to the naked 

 eye, and with the mouth opening obliquely on the free surface of the placental zone (fig. 

 10a). In many of these larger openings the end of a longer chorionic villus was inserted, 

 and as the base of the villus had torn away from the chorion in the act of separation of the 

 fcetal placenta, these longer villi were left attached to the maternal part of the placenta. 

 A careful survey of the whole surface of the zone showed only three patches devoid of 

 crypts, the largest of which was If inch in length by 1 inch in breadth, whilst the 

 smallest was 9 mm. by 5 mm., and it is possible that these may have been due to the 

 abrasion of the crypts from the surface. 



The crypt-like or spongy layer of the maternal placenta varied in thickness from one- 

 third of a millimetre to nearly one millimetre. When vertical sections were made through 

 it, and examined with a magnification of 60 diameters, the crypts were seen to pass from 

 their orifices on the free surface, usually with a considerable obliquity either as far as or 

 almost as far as the attached surface of the crypt layer. As a rule, they were elongated 

 and tubular, and conformed to the shape of the chorionic villi which they had originally 

 contained. Opening into them were smaller secondary crypts, which were cut across in 

 the sections, so that the spongy character was not limited to the surface, but prevailed 

 throughout the entire thickness of the crypt-layer (figs. 11, 12). The crypts and their 

 subdivisions were separated from each other by slender and delicate bands of the mucous 

 membrane. The crypts were lined by an epithelium, the cells of which were in part in 

 apposition with their walls, and in part had become detached, and were lying loose in their 

 cavities. Under higher powers, it was seen that the cells varied in shape ; some were 

 longer in one diameter than in the opposite, though the elongation was not so great as to 



