118 PH11.0S0PH1CAL TKANS ACTIONS. [aNNO 1704. 



to draw the penis within the cloaca after an erection; hh two other muscles 

 which serve for the same use, and arise from the rectum, but are fixed to the 

 opjX)site part of the corpora cavernosa penis; i the urethra where it has no 

 glandulous body inclosing it; kk the prostatas or corpus glandosum, inclosing 

 the urethra, which lies contorted between the penis and the bladder of urine, in 

 the pelvis of the abdomen of this animal; mn two mucous bags on each side^ 

 at the root of the penis, which empty themselves into the urethra; oo the 

 bladder of urine; pp the musculi cremasteres; qlq. the left cremaster muscle, 

 inclosing the tunica vaginalis; rr the tunica vaginalis of the right side, opened 

 to show the inclosed vasa praeparantia and vas deferens; ss the vas deferens; 

 TV the tunica vaginalis inclosing the left testicle, with its epididymis v; wxyz 

 the right testicle, as it appeared on opening the tunica vaginalis; w its epididy- 

 mis; X the body of the testicle ; y the spermatic vein and artery, as they pass 

 to and from the testicle; z the excretory duct of the testicle, which could be 

 distinctly seen arising from the testes, and proceeding to the epididymis w, where 

 it is folded up and constitutes that body, whence it is continued to the bladder 

 of urine, and called vas deferens ss; a a the spermatic arteries, arising from the 

 forepart of the descending trunk of the arteria magna, where they have a com- 

 mon duct, which is divided as it passes through an aperture made on purpose in 

 the trunk of the vena cava; bb the spermatic veins at their entrance into the 

 cava; dd the kidneys ; ee the ureters; gg the emulgent veins; ^ part of the 

 left emulgent artery; h the vena cava below the liver; ii the descending trunk 

 of the great artery ; kk the mesenteric arteries ; 1 the lower mesenteric artery 

 which in this animal does not arise from the great trunk ; m the left glandula 

 renalis, that of the right side being placed behind the trunk of the vena cava n ; 

 o a common trunk of an artery, from whence springs the gastric, the superior 

 and inferior mesenteric, and the emulgent arteries of this animal. The design 

 of nature in confining all those arteries to one trunk in this animal, might be 

 perhaps in favour of its usual posture in hanging by its tail, with its head down- 

 wards. This trunk of the arteries of the viscera of the lower belly, having so 

 many united forces, is the less liable to any compression, that might be made 

 by the contained parts of the lower belly in that posture. 



Fig. 3 represents the backside of the genitals of the male opossum; a the 

 body of the penis; b its glans; cc the bulbi of the corpora cavernosa penis, 

 covered with their muscles; dd the corpora cavernosa penis; be the two 

 distinct bulbs of the cavernous body of the urethra, inclosed with their particu- 

 lar muscles; ffg parts of the muscles expressed on the forepart of the penis in 

 the preceding figure; hh the other pair of muscles springing from the rectum, 

 and inserted into the sides of the corpora cavernosa penis; ikl the urethra 



