316 



DIDELPHTIDJS. 



The Opossums take the place in the Neotropical region of the 

 Inseotivora of other parts of the world, the great majority being 

 arboreal, and to this extent corresponding to Tupaia, while a few 



Kg. 6. 



Didelphys marsupialis. — Jaw and hind foot, showing combination of polyproto- 

 dont dentition with a nou-syndactyloua foot. 



{subgenus Peramys) are more or less terrestrial, and strongly re- 

 eemble the Shrews both in appearance and habits. One single 

 species, Chironectes minimus, is aquatic. 



Sytiopsis of Genera*. 



A. Hind toes quite free 1. Didelphys, p. 316, 



B. Hind toes webbed to their extremities 2. CmnoNECTES, p. 30G. 



1. DIDELPHYS. 



Didelphys t, Linn. Sijet. Nat. (10) i. p. 54 (1760) 



Type. 

 D. marsupialis. 



* It is impossible to find any single cranial character by which Chironectes 

 naay be distinguished from all the species of Didelphys, but in order to assist 

 in its recognition a reference is made to its skull in the cranial synopsis of the 

 species of that genus. 



t For the full recent synonymy of the genus see •(»/)■<> under the different 

 subgeuerio headings, and for the fossil svnonyms sco LydekUor, Oat. Foss. 

 Mamin. B. M. y. p, 278 (1887). 



