182 



of this process is 1 inch, and it advances -^ an inch beyond the gle- 

 noid cavity. 



" The clavicle is slender, 1 inch 5 lines ong, with a slight sig- 

 moid flexure. 



" The humerus presents nothing very remarkable ; its length is 1-|- 

 inch. 



" The pelvis is long and narrow ; its breadth from point to point 

 is 3^ inches ; its length, 5 inches ; the depth of the symphysis pubis, 

 1-1- inch. 



"The femur is thin and small, and has both a. trochanter major 

 and a trochanter minor. 



" In the motions of the hinder limbs of the Coypus when alive I 

 obser^^ed not only an awkwardness, but a want of firmness, which 

 gave something of a crawling character to the progression of the 

 animal on the floor. A recollection of this circumstance, which 

 struck me when I first saw the animal, led me to open the capsule 

 of the hip-joint with care : on doing this, I was surprised to see no 

 ligamentum teres : on opening the other, still none appeared. I am con- 

 vinced that I did not destroy or rupture the ligament, for no ruptured 

 fibres were at all visible, and on opening the acetabula of other 

 animals at the same time, the ligament was found strong and large ; 

 in this, however, nothing of the kind was visible. There is on the 

 head of the femur a very slight depression, but it is covered, as 

 the rest of the head, with smooth cartilage. I believe, therefore, 

 that the Coypus may be added to the list of the few Mammalia in 

 which this ligament is absent : but it would be desirable that ano- 

 ther specimen should be examined before this peculiarity is insisted 

 on as an ascertained fact. 



" The ribs are short, thin and flexible, the longest measuring only 

 3 inches exclusive of the cartilage ; the first two are very short, but 

 strong. The chest of the Coypus is, in fact, of very small capacity. 

 The number of the ribs is thirteen. 



"The spinous process of the first dorsal vertebra is very short, 

 like those of the cervical vertebra; but that of the second rises 

 abruptly to the length of 1 inch, which is at least a quarter higher 

 than those of the succeeding vertebra. 



" The number of the vertebra is as follows: — 



Cervical 7 



Dorsal 13 



Lumbar 6 



Sacral 4 



Caudal 23 



" I regret that I was unable to examine all the bones of the extre- 

 mities, as Cuvier notices a peculiarity in those of the carpus, — in 

 there being no separation between the os magnum and trapezdides." 



Mr, Christy subsequently exhibited several skins of the Coypus, 

 for the purpose of directing the attention of the Meeting to the po- 

 sition of the mamma in the female, which are situated extremely high 

 up the sides. 



