FCETAL MKMBKANES OF CHIROMYS MADAGASCAKIENSIS. 1161 



In Chiro'm'i/s, the vesicles are evidently not of the same 

 functional importance as in Nycticehus and Galago, and it niay 

 be suggested that they serve not so much as absorptive organs, 

 but rather as reservoirs for the surplus of the uterine-gland 

 secretion which is probably in major part absorbed directly by 

 the trophoblast of the laminar villi. 



The general occvu-rence of chorionic vesicles in the Lemuri- 

 formes has not so far been established. The only reference to 

 their presence that we know of is an inconclusive statement by 

 Strahl (15) that in Lemur mongoz., he observed a.t one place an 

 indication of a chorionic vesicle devoid of internal villi, overlying 

 a oTOOve in the mucosa whicli might be a uterine gland area. 

 But what apparently does characterise the chorion of certain oi 

 the Madagascar Lemuis, e. g. Propithecus, is the occurrence 

 of circumscribed chorionic bare patches, opposite which there 

 occur on the mucosa depressed bare areas on which the uterine 

 glands open. Such complementary bare areas (and more espe- 

 cially the uterine) have been described by Milne Edwards and 

 Turner (with excellent figures of the uterine areas, 3, p. 280, 

 and 5, figs. 8 & 9), and more recently by Strahl (15, figs. 14, 15, 

 16, ik 18 a & &), but none of these observers has given any 

 account of the structure of the chorionic ai'eas, though Turner 

 (5, p. 582) expressly states that "the smooth, non-villous sur- 

 faces of the chorion opposite the smooth areas on the mucosa are 

 engaged in the absorption of the secretion of the glands." 



In the course of examining our preparations of the late 

 Dr. Jenkinson's material of Lepileniur, we observed what Ave 

 took to be these particular areas ; and on referring again to 

 Dr. Jenkinson's paper, we realised that his description (16, p. 180} 

 of the simpler conditions in what he terms "the non-placental 

 [really non-villous] regions," illustrated in his figs. 3-7 and 15, 

 actually refers to the areas which we had identified as the bare 

 areas of previous investigators. As Jenkinson describes, 

 these non-villous areas are characterised by the transformation 

 of the trophoblast covering them, into a thick layer composed of 

 elongated narrow columnar cells, measuring up to •063 mm. in 

 height and just about six times as thick as the normal tropho- 

 blast covering the villi (c/. Jenkinson's figs. 3, 4, &, 5). The 

 cytoplasm of the cells is lightly staining and coarsely reticular in 

 character, and in some of the cells there is a large, clear vacuole 

 situated in the basal part of the cell, below the nucleus. The 

 nuclei are oval and deeply staining, and are situated near the 

 middle of the cell-bodies, though sometimes the}^ approach their 

 free surface. Occasional binucleate cells were observed. Specially 

 characteristic of this epithelium is the production of the outer 

 ends of the cells into bluntly tapex-ing or knob-shaped processes, 

 in which, occasionally, a more or less shrivelled nucleus may be 

 seen. They project into a granular material, " apparently a 

 secretion of the uterine epithelium," according to Jenkinson, and 

 are no doubt absorptive in function. In the basal part of the 



