246 RODENTIA. 



its body, to near the glans or last turn, and then enters the urethra 

 itself. "When these bodies are cut into, they look something like the 

 testes in structure. The prostate is a pretty large body, much of the 

 figure of a heart as it is painted upon cards, not so sharp pointed at the 

 apex, but sharper pointed at the two bases ; it is placed at the under 

 surface of the urethra, a little way beyond where the bladder has 

 become small; it is loose at both ends, only being attached to the 

 urethra by loose cellular membrane. This is something like the human ; 

 but it does not surround the urethra ; the urethra at the bulb is rugous, 

 and penniform 1 . There is something very particular about the penis 

 and urethra that I could not examine. (It is just the same in the 

 English squirrel 2 .) 



The contents of the thorax are as in a dog ; there is a cavity for the 

 oesophagus as in the other [squirrel], and there are two vense cavae, as 

 in the goat, rat, &c. The right subclavian and two carotids arise by 

 one common trunk from the aorta, and the left subclavian by itself, so 

 that only two arteries arise from the curve of the aorta. 



The Flying Squirrel [Pteromys (Sciuroptei-us) volucella]. 



The thorax is much flatter than is commonly found in quadrupeds, 

 and increases in breadth very far downwards, something like the mouth 

 of a French horn. The pectoral muscles seem to be thicker than in 

 other animals of the same size. The fore-legs do not fall down parallel 

 with one another by the side of the trunk, so that the scapula may 

 stand almost perpendicular, but pass out almost transversely from the 

 body, so that the scapula lies flat upon the flattened chest almost as in 

 the human subject. The belly is likewise flattened, and the thigh- 

 bones are turned out ; so that the adhesion between the muscles of the 

 thigh and belly that we find in quadrupeds is not to be found here, for 

 they are as much detached as in the human. 



This circumstance of the whole length of the fore-legs passing out 

 almost transversely, and likewise the thigh-bones of the hind-legs, gives 

 attachment to the skin that is extended between the two limbs. But 

 from the skin being attached to the whole length of the fore-leg as far as 

 the wrist, and only to the thigh-bone of the hind-leg, the anterior part 

 is much broader than the posterior ; and along the edge of this mem- 

 brane, for about 1 inch at the anterior end, there is a cartilage as if it 



i [Hunt. Prep. No. 2498.] 



2 [It would seem that Hunter had procured a male specimen when he entered 

 this remark. The bones of the Sciurv.s vulgaris are numbered 2268 — 2286, Hunt. 

 Osteol. Series.] 



