MORPHOLOGY OF THE HUMAN URINOGENITAL TRACT. 347 



V. The Genital Tract in the Marsupialia. 



I have examined the genital tract in seven specimens. Two 

 of these were what is termed the Eat Kangaroo {Hypsiprymnus)^ 

 two were "Wallaby kangaroos, and three were specimens of 

 Bennett's kangaroo {Macropiis Benneti). I am indebted to the 

 Marquis of Bute for the Wallaby kangaroos, to Professor 

 Symington for the pelvis of one of the Bennett's kangaroos, and 

 to Professor Kelly of Baltimore for one of the opossum. The 

 rat kangaroos were obtained alive, and I was thus enabled to get 

 the genital tract fresh and in good condition for microscopical 

 examination. In one I therefore had serial sections made of the 

 whole genital tract, so that the complicated structures might be 

 traced accurately. This involved the preparation of about two 

 thousand slides on this question alone. The other specimens 

 were examined for their naked-eye relations, and drawings made. 



I purpose, therefore, under this heading to consider — 



1. The naked-eye. anatomy of the Kangaroo genital tract. 



2. The microscopical serial sectional anatomy of the genital tract 



in the Hat Kangaroo. 



1. The naked-eye anatomy of the Kangaroo genital tract. — 

 In the Marsupials we have a very remarkable arrangement 

 in the vaginal portion of the genital tract. The uterus is 

 bicornuous, and each horn has its lower opening or os uteri. 

 The vagina has two lateral canals, which may arch and meet 

 above, this portion lying between bladder and uterus like a 

 second bladder. Below, these so-called lateral canals open into 

 the urinogenital sinus. In addition, a median portion is present, 

 and this communicates above with the lateral canals, while below 

 it may end as a cid-de-sae, or in some species open into the 

 urinogenital sinus. In the central portion, Ihe double os uteri 

 opens. Lister and Fletcher discuss the condition of the median 

 portion in the Alacropodidae carefully, and give a table of the 

 various species, and the arrangements in each as to this point. 

 Some allege that the opening is not present in the same animal 

 in its early life. Figs. 27, 28, and 29 give the variations, so 

 far as known, in the diftereut species of marsupials. These 

 authors also figure the relations of the Wolthau ducts and ducts 



