162 Dynamic Theory. 



the climbing Cyclothurus didactylus, South American Ant-eater, \vhile 



other species do not have any. 



FIG. 85. Part of Skeleton of 

 Ichthyosaurus (Extinct Gi- 

 gantic Saurian. (After Hux- 

 ley.) 



A Pectoral Arch, 

 co, Coracoid. 



sc., Scapula. 

 cl, Clavicle. 

 id, Inter-clavicle or Epi- 



sterinim. 

 B-Pelvic Arch. 

 il, Ilium. 

 is, Ischium. 

 pb, Pubis. 



The rodents, Squirrels, &c., "generally possess clavicles, but the 

 Guinea-pig is an exception. 



Clavicles are completely developed in all the Insect ivora except Pota- 

 mogale. In the Moles they are very strong. 



In the cheiroptera, Bats, &c. , the clavicles are remarkably long and 

 strong, and the broad scapula has a strong spine. 



The Apes and Man possess clavicles and the coracoid rudiment. In 

 all the cases cited above of animals possessing coracoids or clavicles or 

 both, the fore feet or hands are used for other purposes besides walk- 

 ing as swimming, flying, climbing, digging, grasping, etc. 



But now, coming to animals whose chief use of the fore limbs is in 

 walking, we find things different. In all the carnivorous animals the 

 clavicle is incomplete. In the dog it is represented by a gristle. 



In the carnivores, generally, the clavicles are more or less rudimen- 

 tary, and when ossified at all are simply suspended in the muscles and 

 not articulated to the sternum. This family includes the Bears, Rac- 

 coons, Badgers, Weasels, Martens, Otters, Skunks, &c. , as well as the 

 Dogs, Wolves, Foxes, Hyaenas, Cats, Lynxes, Lions, Tigers, Panthers, 

 &c. Some of these animals do more or less digging and burrowing, 

 while others are fair climbers. Yet the burrowing of most of them ex- 

 tends no further than the excavating of one or two holes during a life- 

 time, and their climbing, to an occasional dash up a tree ; not compara- 

 ble, in the first case, to the life-long tunnelling of the Mole for his daily 

 bread, or, in the second, to the perennial leaping and swinging of the 

 Apes from branch to branch. 



The case of the Ungulates, or hoofed animals, is much more pro- 

 nounced, for they do not, in any case, possess clavicles. These animals 

 are divided into the Pachyderms, which include the Elephant, Pig, Hip- 



