ACCOMMODATION AND CONVERGENCE 



59 



the eyes of a cat and then allowed it to pursue a mouse, 

 which it caught without any difficulty. 



I have examined microscopically sections of the ciliary 

 body from the eyes of mammals belonging to various dif- 

 ferent natural orders, and find that the degree of develop- 

 ment of the ciliary muscle corresponds fairly accurately 

 with the degree of capacity for accommodation which* the 

 animal has been found to possess. 



Fig. 10. — Ciliary body of the great ant-eater. 



In some of the lowest mammals, such as the echidna 

 (Fig. 9) and the great ant-eater (Fig. 10), the ciliary muscle 

 is practically non-existent. In rabbits (Fig. 11) only a 

 few scanty fibers are recognizable. In the marsupials 

 (Fig. 12) there is a small definite bundle of longitudinally 

 placed fibers. In the Ungulata (Fig. 13) and Carnivora 

 (Fig. 14) the longitudinally directed fibers are more numer- 



