PTEROMYS VOLUCELLA, 247 



were folded in it. This cartilage is fixed at one end to the carpus at 

 the inner edge, thence passing into the doubling of the membrane where 

 it is becoming smaller, ending in a point, and is a little curved, with 

 the hollow side turned down. This cartilage is moveable upon the 

 carpus, and has muscles inserted into it for its motion, viz. the flexor 

 carpi ulnaris ; and is what answers to the os pisiforme in us. 



The skin of this animal is in general very loose ; and, when the 

 legs are stretched out transversely, they seem to draw a great deal of 

 skin from the body to be stretched between the fore- and hind-legs ; 

 but this membrane is not entirely a doubling of the skin of the body so 

 as to be wholly at times doubled, and at other times not ; for the outer 

 edge is always doubled like a duck's foot, even when the animal is 

 walking, which is the most relaxed state of this membrane j and, at 

 times, we may observe a ridge passing along the side of the animal, 

 which te rmin ates the two colours of the hair ; for on the belly it is 

 white. 



As the whole body of this animal is very flat, the anus appears to be 

 almost at the termination of the abdomen. The testicles he upon the 

 abdomen [when the body is supine], and the penis reaches almost half- 

 way up the belly. 



The heart is as in the common squirrel, having the two vense cavse 

 superiores. 



The stomach is short and thick j there is a long projection of the 

 great end beyond the oesophagus, and it becomes pretty suddenly small 

 at the pylorus : its coats are but thin, and equally so all over. The 

 pylorus is a little upon the right of the spine : the duodenum is loose 

 from the pylorus to its passing across the spine, where it inclines 

 upwards, and is attached by a thin membrane to the root of the mesen- 

 tery and to the spine ; it then again becomes a loose intestine. The 

 ileum enters the colon on the middle line of the abdomen, and the 

 csecum lies chiefly on the left side, projecting about 2 inches beyond 

 the insertion of the ileum ; it is a little bent by a narrow mesocaecum. 

 The colon on the right side, before it crosses the spine, makes a fold 

 upon itself, about 2 inches long ; and, when it passes across the spine, 

 it makes a very faint one ; it then passes down upon the left and to the 

 anus 1 . 



The epiploon is attached to the stomach, spleen, and pancreas : it is 

 pretty broad and flat. The pancreas has two lobes, the small one close 

 to the duodenum, and the union of the two is close to the pylorus. The 

 liver is divided into four lobes besides the lobulus Spigelii ; the two 



1 [Home, Cornp. Anat. p. 451.] 



