l48 NOTES ON MARSUPIALIAN ANATOJfY, 



two separate outgrowths approximating, but hardly suf- 

 ficiently to form a homogeneous structure. Van den Brock 

 has said: — "Man konnte in diescr doppclten Herkunft 

 Anlass finden statt von cincm 'Sinus vaginalis' von 'Sinus 

 vaginalcs' zu sprechcn, " and this statement ajjplies above 

 all to the condition iu Sarcophilus. 



MICROSCOPIC STRUCTURE. 



Muscularis. — In common with Hill and Van den 

 Broek, I find that, as in tlic I'est of Marsupials, the mus- 

 cular tissue of the median vaginal apjjaratus consists of 

 circularly running nonstriatc fibres. On this point, how- 

 ever, the latter says (3, p. 60): "Muskelfaseni kommen 

 iiiemals in Septum vor, die. . . Muscularis circularis in der 

 Wand des Sinus umschliesst immer die beiden llohlraumc 

 dos Sinus als eincn einheitlichen Raum." Hill, however, 

 (5, Y>. 53) says of the two cul-de-sacs in the virgin Perameles 

 that "they are separated by a common j)artition wall, and 

 each is surrounded by a delicate layer of circular non- 

 striate fibres." He refers to Fig. 7, but the presence of 

 these fibres in the septum is more plainly and unmistak- 

 ably shown in Fig. 10 of a section through the median 

 vaginal cul-de-sac of a specimen with two 17.5 young in 

 the pouch. 



In Sarcophilus 1 find that each sinus is contained in 

 its own portion of circular muscle, which wholly surrounds 

 it, and is, therefore, present in the septum. The presence 

 of these muscle fibres in the septum of both Perameles and 

 Sarcophilus gives the two median vaginal cul-de-sacs an 

 independence which is absent in other marsupials. In 

 Sarcophilus I find that the epithelial lining of the vaginae, 

 median cul-de-sacs, and of the necks is of practically thi. 

 same character throughout, consisting of an overlying layer 

 of flattened cells which is not at all continuous, below which 

 is a layer one or two cells thick of cells containing rounded 

 nuclei. The epithelium of the urogenital sinus is similar. 

 I have already (10) shown that tiic posterior ends of the 

 median vaginal cul-de-sacs are embedded in a mass of 

 deeply staining connective tissue, continuous with a central 

 mass of similar tissue passing backwards between the 

 lateral vaginae, and coming into relation with them about 

 the point where the two lateral vaginae meet the urogenital 

 sinus. This rod of connective tis.sue is similar to that 

 already described by Hill in Perameles (5. p. 54). This 

 mass of tissue is distinctly defined in the specimen under 



