1162 PROF. J. p. HILL ATsD MR. R. H. BURNE ON THE 



layer, there occur at intervals curious spherical cells, and imme- 

 diately below it, capillaries are present in fair abundance. 



The utei-ine areas, related to the just-described characteristic 

 areas, are more or less folded, and may or may not be depressed. 

 They are characterised by the marked thickening and ridging of 

 the uterine epithelium, and by the presence of the openings 

 of the uterine glands. The uterine epithelium appears as a 

 deeply staining layer, thrown into low ridge-like folds (Jenkinson, 

 fig. 15) and about live times as thick as the ordinary epithelium 

 covering the mucosal folds. It is composed for the mdfet part 

 of narrow columnar or club-shaped cells, with deeply staining 

 cytoplasm and chromatin -rich nuclei. Jenkinson records the 

 presence of goblet cells amongst the ordinary epithelial cells, but 

 wo have failed to detect them, and considers the epithelium is 

 secretory. However that may be, and it is probable, coarsely 

 granular material similar to that found in the uterine glands 

 occurs in the interspaces between the thickened trophoblast 

 and the ridged uterine epithelium ; and there can be no doubt, 

 we think, that these non-villoiis chorionic areas have the same 

 functional significance as the chorionic vesicles of the Lorisi- 

 formes. Indeed, in view of the close adherence of the uterine 

 epithelium to the trophoblast of the chorionic villi, characteristic 

 alike of Propithecus (Strahl) and Lepilemur (Jenkinson), special 

 absorptive areas in relation to the openings of the uterine glands 

 would seem to be necessary if the secretion of the latter is 

 to be adequately utilised. 



It may be noted that these area.s attain a relatively consider- 

 able size, as may be judged from Strahl's figures of Propithecus 

 (15, taf. 37). The largest area we have examined in Le2nlemur 

 measures over 3 mm. nr diameter. 



CONCLUSIO^"^. 



In the contribution by one of us (H.) to the discussion on the 

 zoological position and affinities of Tarsius (17), the view is 

 expressed (p. 477) that the placentation of the Lemuroids 

 is essentially primitive, " presenting us with a simple little 

 specialised type of placenta from which the more advanced and 

 presumably more efiicient arrangements in the other Primates 

 may quite easily have originated as the result of adaptive 

 specialisation in the course of evolution.'"' More detailed 

 acquaintance Avith the Lemuroid placenta has only served to 

 strengthen us in that conclusion, and has, moreover, entirely 

 failed to reveal the slightest evidence in support of the view 

 expressed by Hubrecht (10, p. 145) and also by Assheton 

 (18, p. 268) that the Lemuroid placenta is a secondarily simplified 

 and derivative type. 



These two authorities base their belief very largely on 

 theoretical considei'ations concerning placental evolution, and 

 consider that the diffuse placenta of the Lemui-s is difFei-ent from 

 that of the Ungulata, Manidfe, Cetacea, etc. 



