1881.] VAGINAL APPARATUS IN THE MACUOPODID^. 9H7 



into the cavity of the canal just heyond the constriction, vvhich is so 

 arranged as to form a valvular barrier to a body passing up the 

 canal. 



We have been unable to obtain any history of the second specimen 

 of M. major, from the Museum at Cambridge. 



The median vaginal canal had been opened in order to display the 

 interior. The remains of a median septum were visible, and, besides 

 this, two low crescent-shaped folds of the lining menbrane, which 

 extend with their concavity forward from the middle line of the ventral 

 wall to the sides. The median canal when traced back becomes 

 much narrowed ; it can, however, be followed to a point where it abuts 

 against the left lateral canal just as this opens into the urogenital 

 chamber — at a point, that is, just to the left of the middle line. 

 Although our specimen thus agrees with those of other observers, 

 in the fact that the median chamber is a cul-de-sac, it differs from 

 them in the fact that the walls are continuous by means of their 

 proper tissue with those of the lateral and urogenital canals. 



Halmatums bennetti exhibits the open condition of the median 

 canal. There were well-marked muscular thickenings in the lateral 

 canals, but no valvular folds. 



Halmaturus derhianus (no history) was in a similar condition ; but 

 the valvular fold was well marked. 



The specimen a of Ilulmaturus ualabatus was the first example 

 in which our attention was drawn to the subject. 



It died in the Society's Gardens on June .30th. The measurement 

 from the nose to the root of the tail was 16 inches — that is, 1 2 inches 

 shorter than its mother. It was bred in the Gardens, and was 

 taken on the list of the Society's collection on May 19th, i. e. at the 

 time when it was old enough to leave the mother's pouch. 



The evidence that she had not born young appears to us 

 conclusive. 



It will be observed that only 42 days had elapsed between the date 

 of entry on the list and tiie date of death ; so, if young had been pro- 

 duced, it must have been during that period. The period of gestation 

 which Prof. Owen gives for Macropus major is 39 days. Assuming 

 a period of about the same length for H. ualabatus, we must sup- 

 pose that, if _voung had been produced, it was born towards the 

 end of those 42 days, so that lactation would be at its iieight at the 

 time of death. Now it was observed at the time (1) that there were no 

 young in the pouch, and (2) that the teats were so small as not at 

 first to be recognized ; for we find from the notes taken at the time 

 that it was not till after a second more careful examination that the 

 four minute teats were seen, arranged in a crescentic line on the body- 

 wall of the pouch. 



We may take it for certain, then, that the specimen examined had 

 not born young. 



The arrangement found was as follows (see fig. 2, p. 988): — The 

 median vaginal canal was wide in front and gradually contracted 

 posteriorly, where it passed by a distinct opening into the urogenital 

 chamber just above the opening of the urethra. The lateral canals 



