238 GEOGRAPHICAL ZOOLOGY. [part iv. 



The Octodontidas include a number of curious and obscure 

 rat-like animals, mostly confined to the mountains and open 

 plains of South America, but having a few stragglers in other 

 parts of the world, as will be seen by our notes on the genera. 

 The most remarkable point in their distribution is, that two 

 genera are peculiar to the West Indian islands, while no species 

 of the family inhabits the northern half of South America. 

 The distribution of the genera is as follows : — Habrocomus (2 

 sp.), Chili ; Capromys (3 sp.), two of which inhabit Cuba, the 

 third Jamaica (Plate XVII. vol. ii. p. 67) ; Plagiodontia (1 sp.), 

 only known from Hayti; Spalacopus, including Schizodon (2 

 sp.), Chili, and east side of Southern Andes ; Octodon (3 sp.), 

 Peru, Bolivia, and Chili ; Ctenomys (6 sp.), the tuco-tuco of the 

 Pampas, the Campos of Brazil to Bolivia and Tierra del Fuego ; 

 Ctenodactylus (1 sp.), Tripoli, North Africa ; Pectinator (1 sp.), 

 East Africa, Abyssinia, 4,000 to 5,000 feet. 



Capromys and Plagiodontia, the two West Indian genera, 

 were classed among the Echiniyidse by Mr. Waterhouse, but 

 Professor Lilljeborg removes them to this family. 



Extinct Octodontidw. — Species of Ctenomys have been found 

 in the Pliocene of La Plata, and an extinct genus Megamys, said 

 to be allied to Capromys, in the Eocene of the same country. 

 In Europe, Palceomys and Archccomys from the lower Miocene of 

 Germany and France, are also said to be allied to Capromys. 



Family G5.— ECHIMYID/E. (10 Genera, 30 Species.) 



The Echimyidre, or spiny rats, are a family, chiefly South 

 American, of which the Coypu, a large beaver-like water-rat 

 from Peru and Chili is the best known. Two of the genera are 

 found in South Africa, but all the rest inhabit the continent of 

 South America, East of the Andes, none being yet known north 



