CASTOR CANADENSIS. 225 



are flattened sideways ; each has a claw, and their motions are more 

 determined. The hind- legs are strong ; the feet are broad, and webbed 

 like those of a seal ; and the muscles of the abdomen adhere to the 

 inside of the thigh, something like the seal's ; and what answers to the 

 little toe is the strongest, as in the fore-foot, bnt not so remarkably. 

 The insertion of the abdominal muscles into the pubis is at the lower 

 edge, which rises so that the whole anterior part of the surface of the 

 pubis makes part of the cavity of the belly. The hind-legs are capable 

 of being extended backward, for the purpose of swimming, farther than 

 in animals in common. Indeed, this animal is fitted for that action in 

 many respects ; as, e. g., the testicles are not loose and pendulous, but 

 flat, and in some measure buried on each side of the rectum ; so that 

 there is nothing to retard the motion through the water. 



The parotid gland is very large, so much so as to cover almost the 

 whole fore-part of the neck, joining its fellow, before, at the thyroid 

 gland : its duct passes over the masseter muscle. The thyroid is also 

 large, of a dark purple, and comes below the upper part of the sternum, 

 so as to appear like the thymus. The tongue is not flat and edged ; 

 but is thick at the fore-end, its two broadest surfaces being re- 

 versed, viz. they are lateral; the mouth is so narrow between the 

 grinders and incisors, that the tongue there adheres to the lips or cheek. 

 There are a vast number of glands about the mouth. The eyelids are 

 very small, which is contrary to most of the present order. The fat of 

 this animal is principally on the external surface, immediately under 

 the skin ; there is little or none in the interstices of the muscles, and 

 hardly any in the abdomen anywhere. 



The oesophagus is long below the diaphragm, as in the rat : at the 

 insertion of the oesophagus [into the stomach] there is a glandular body 

 that appears upon the external surface like a distinct cavity ; its ducts 

 open into the stomach upon a flat surface 1 . The stomach is large and 

 wide ; it makes a pretty quick turn near the pylorus. The duodenum 

 passes down the right side nearly as low as the pelvis ; then turns up 

 by the side of the rectum, adhering to that gut ; then gets on the left 

 of the mesentery, where it becomes loose. The ileum enters the colon 

 in the middle of the body just above the pelvis ; and the caecum passes 

 to the right, making a quick turn upwards, and to the left, behind the 

 mesentery ; so that the apex of the caecum lies on the left side. The 

 csecum is wide at the beginning, and is about 18 inches long. 



The colon passes to the left, then makes a quick turn upon itself to 

 the right, crossing the pelvis, the two portions adhering together ; it 



1 [Hunt. Preps. Nos. 587 — 598 ; Home, Comp. Anat. i. p. 145. tab. xiii.] 

 VOL. II. Q 



