112 PHILOSOPHICAL TRANSACTIONS. [aNNO 1704. 



the name of hyoides, from the figure they make with the ossa pubis of this 

 animal ; which bones seem not to differ in the male, from those of the female 

 he has described and figured in the Transactions referred to. 



There is no external appearance of genitals in the male opossum, but the 

 scrotum; which is but just large enough to contain the testes; nor could I 

 readily discover any other foramen outwardly in these parts besides the anus, 

 a, (pi. 5, fig. l) which leads to the rectum ; but on withdrawing its sides, I 

 found another foramen, b, which on dissection appeared to be the praeputium 

 or out-let of the penis. On compressing the parts on each side this cloaca, 

 A, B, I observed two drops of yellowish coloured liquor, resembling pus, start 

 out on each side the anus, cc, which on further examination I found come 

 from two glandulous bodies, or bags, placed on the sphincter muscle of this 

 part. This sort of liquor it seems Dr. Tyson found in the pouch of the female, 

 which, like this, had more of the peculiar foetor of this animal, than any other 

 part besides; for on removing these parts with the skin about the cloaca, I was 

 freed from the ungrateful smell. On separating the skin from the muscles of 

 the abdomen, the two bones above-mentioned (peculiar, I believe, to this 

 animal) appeared, from whence some muscles sprang, and were inserted into 

 the ossa femorum, which performed the office of the psoas muscles in other 

 animals, which last named muscles were much smaller in this, than in other 

 animals. 



The abdominal muscles were also fastened to the last mentioned bones, par- 

 ticularly the recti, which enabled this animal to project or spring its body, espe- 

 cially in drawing its hind legs forward, with more advantage or force than 

 other animals. Immediately under the skin about the cloaca I found a thin 

 fleshy muscle, inclosing the praeputium, and the lower parts of the rectum and 

 odoriferous bags, together with the four mucous glands, mmnn, fig. 2, 3, at 

 the root of the penis, and body of the penis itself a ; all which parts were 

 liable to be compressed by the action of this muscle, especially when the penis 

 is erected, by which its erection is sustained by compressing the two external 

 veins on the dorsum penis. On removing this thin broad sphincter muscle, I 

 was obliged to clear away two lumps of hard fat, before the body of the penis 

 could be discovered. 



The scrotum being removed, each testicle appeared as represented on the left 

 side QTv, fig. 2, the vasa praeparantia and deferentia qq being inclosed in the 

 cremaster muscles pp. These muscles were propwrtionably very large in this 

 animal, as I have always observed them in those that have no vesiculae seminales, 

 which is the case of this animal ; and this provision of nature seems not only 

 necessary to suspend the testes, but these inclosing cremaster muscles also com- 



