522 FEMALE UROGENITAL ORGANS IN THE MARSUPIALIA, 



From the foregoing account it will be seen that while the 

 female genital organs of Myrmecobius agree in certain important 

 respects with those of Perameles, as described in Contribution I., 

 they also exhibit certain well marked differences. The two forms, 

 Myrmecobius and Perameles, agree — (1) in the possession of a 

 relatively small median vaginal apparatus, consisting in virginal 

 animals of two quite separate cul-de-sacs, and completely imbedded 

 in the tissue of the genital cord. (2) In the absence of any well 

 marked separation between the uterine necks and the median 

 vaginae, the former passing over directly into the latter without 

 the intervention of distinct ora. (3) In the relations of the 

 morphologically anterior, forwardly directed portions of the 

 lateral vaginae which remain permanently imbedded, with the 

 uterine necks and the median vaginae, in the tissue of the genital 

 cord, and thus retain the position and course presented by the 

 Mullerian ducts in the foetus. And (4) in the possession of a 

 distinct cloaca. In these four respects the genital organs of 

 Myrmecobius exhibit what I have regarded as primitive features. 



As regards the points of difference in the organs of the two 

 forms, two are worthy of remark — (1) the freedom in Myrmecobius 

 of the middle portion of the lateral vaginae and their coiled 

 character, and (2) the presence in the same of a long urogenital 

 sinus. 



In dealing with the genital organs of Perameles, I pointed out 

 that the genital cord of the foetus is there retained practically 

 unaltered as the urogenital strand of the adult, in the connective 

 tissue constituting which the lateral vaginae remain permanently 

 imbedded. In the adult Myrmecobius, on the other hand, only 

 the anterior forwardly directed portions of the lateral vaginae and 

 their posterior ends retain their primitive position in the tissue 

 of the genital cord. Their middle portions have become free 

 from that tissue and taken on a curved course. In this respect, 

 therefore, and in the possession of a long urogenital sinus, the 

 female genital organs of Myrmecobius exhibit less primitive 

 relations than those of Perameles. 



