INTESTINAL TKACT OF MAMMALS. 



517 



Much less attention has been given to the equally interesting fact that there not 

 infrequently occurs a paired condition of the caeca in which the usually suppressed 

 member of the original pair is vestigial. Meckel (14) states that this occurs in some 

 Marsupials. I have found it in several species of Macropus (fig. 8, p. 452) and in Petaurus 

 sciureus (fig. 47, II, p. 518). I have already discussed its occurrence in the Wombat 

 {supra, p. 449). Amongst the Edentates I found it in Bradypus inf meatus (fig. 10, p. 456). 

 In the Common Hare (Lepus timidus) (fig. 46, I) the distal end of Meckel's tract is 



Fig. 46. 



Caeca of Lepus timidus (I) and Ocliolona pusilhi (II). 



C. Cut end of normal caecum. 



II. Cut end of colon. 



C2. Vestigial caecum. 



S.I. Cut end of small intestine. 



inserted between the ordinary very large caecum and a vestigial globular, secorjd caecum. 

 A similar, but not so strongly marked, condition occurs in the Beaver [Castor fiber) ar.d 

 vol. XVII. — paet v. No. 11. — December, 1905. 3z 



