FEMALE ORGANS OF MARSUPIALIA. 683 



broken up into countless oblique rugre and coarse papillae, be- 

 traying a certain regularity in their arrangement : the surface 

 immediately around the urethral orifice is comparatively smooth. 



In Macropus major the vagina?, fig. 538, e, e' , preponderate in 

 size greatly over the uteri c, c ; and, the septum, e f> ', of the de- 

 scending cul-de-sac being always more or less incomplete, a 

 single cavity, e, is thus formed, into which both uteri open ; but 

 however imperfect the septum may be, it always intervenes and 

 preserves its original relations to the uterine orifices, d, d. In 

 the specimen examined by me, this part of the vagina was not 

 continuous by means of its proper tissue with the urogenital 

 canal, but was connected thereto by areolar tissue. 1 In Hal- 

 maturus Bennettii I found an aperture of communication be- 

 tween the median cul-de-sac and the urogenital canal; 2 and, as 

 the same structure has been observed in two other specimens, 3 

 it is doubtless normal, at least, after parturition. The fact, how- 

 ever, does not justify the conclusion that the lateral vaginal canals 

 convey exclusively the semen for impregnation, and that the 

 median canals, which, as a rule, are closed and distinct from each 

 other, serve only to transmit the foetus to the urogenital passage. 

 In Hypsiprymnus murinus the type of construction is the same 

 as in the great Kangaroo, but the mesial cul-de-sac of the vagina 



o o o 



attains a still greater development : it not only reaches down- 

 ward to the urogenital passage, but also expands upward and 

 outward, dilating into a large chamber, which extends beyond 

 the uteri in every direction. From the sides of this chamber the 

 separated portions of the vagina continue downward, to terminate, 

 as usual, in the urogenital canal. 



In Perameles obesula the uteri are wider in proportion to their 

 length than in the Kangaroos. Each communicates with a 



o o 



vagina, expanding into a cascum with semitransparent walls, and 

 greatly surpassing the uteri in size : the ca3ca suddenly contract 

 near the ora tincae, to form long and slender vaginal canals, which 

 converge, but terminate separately near the vulva. The urethra 

 is of corresponding length and tenuity ; its orifice is near those 

 of the vagina, the urogenital passage having the least extent 

 in this genus of Marsupialia. 



In all, the structure of the uteri is distinct from that of the 

 vaginae. The muscular tunic of the uteri is thicker, and consists 

 of an outer stratum of longitudinal fibres, and an inner one of 



1 Removed hy dissection in the preparation, xx. vol. iv. p. 157, No. 2740 c, as in 

 that from which fig. 538 was taken. 2 CCXLIII". p. 106. 



3 CCXLIV". p. 599, and CCXLV". p. 146. 



