&CETAL MEMBRANES OF CHIROMYS MADAGASCAMENSIS. 1149 



in development, occupying the left horn and corpus uteri, with 

 its back turned to the right and presenting with the head. 



This position of the foetus is that generally found in Lemurs 

 towards the end of gestation, though sometimes the foetus may 

 be in the I'ight horn and corpus uteri (Anthony, 12, p. 247 ; 

 Turner, 6, p. 574), and sometimes may ofier a breech j)i'esen- 

 tation (Turner, 5, p. 573 & 7, p. 278) or may lie diagonally 

 (Turner, 5, p. 574). 



In specimen B, so far as we can judge, the elongate embryonal 

 formation lay disposed transversely in the uterus, with the head- 

 end of the foetus in the corpus uteri, directed to the right, its 

 thicker remainder occupying the more extensive left portion of 

 the corpus uteri as well as the left cornu, whilst the chorionic 

 appendage (Pis. III., IV. figs. 5 k 7) projected into the right cornu. 

 The mid-region of the back of the foetus would thus lie closely 

 apposed to the internal os uteri, in a position somewhat similar 

 to that occupied bv one of Turner's specimens of Lemur rufijoes 

 (5, p. 574). 



The wall of the uterus in specimen A is comparatively thin. 

 Its mucous lining (except within the cervix and axound the 

 internal os where it is smooth) is thrown into irregular anasto- 

 mosing folds with intervening depressions, within which are 

 received the villous folds which project from the chorion. The 

 general correspondence between the mucosal folds and depressions 

 on the one hand and the laminar villous folds and the clefts 

 between them on the other is clearly apparent in PI. I. fig. 1, and 

 though both sets of folds are somewhat shrunken, there was clear 

 evidence of close interdigitation between the two. 



In specimen A, the cervix was occupied, as mentioned above, 

 by a conical smooth prolongation of the chorion, but in speci- 

 men B the foetal membranes did not extend beyond the os 

 internum, and the cervix was empty and produced internally 

 into longitudinal folds. The os externum in B projected fi^eely 

 into the vagina and possessed a lobed margin. In A, it was in 

 addition guai'ded by two semi-lunar folds, piojecting from the 

 wall of the vagina., as in the unimpregnated state *. The 

 cervical canal in neither case showed any indication of being 

 closed, as in the human subject, by a plug of secretion. 



In specimen B, the mucosa reaches its maximum thickness in 

 the right cornu, and its folds are here more markedly developed 

 than elsewhere in the uterus, in correspondence with the strong 

 development of the laminar villi on the chorionic appendage. 

 Eound the internal os, as in A, the mucosa is relatively smooth. 



A low-power view of a section through the body of the uterus 

 (specimen B) is reproduced in PI. Y. fig. 12. The muscularis 

 {muse.) though thin relatively to the size of the uterus, is well 

 developed, and in sections in the appropriate plane is seen to con- 

 sist of an outer slightly thicker layer of longitudinal smooth muscle 



* R. Coll. Sui'g. Museum, Physiol. Series, No. 2815 A. 



