OCTODONTID^E 



481 



tion of one species of Echinomys which ranges into Central America. 

 Habits mostly terrestrial, but occasionally fossorial or natatorial. 



Subfamily CtenodaetylinsB. Molars semi-rooted ; jugal as in 

 Dipodidce ; the two inner toes of the hind feet with a horny comb 

 and rigid bristles. Ethiopian region. 



Ctenodactylus. 1 Represented only by C. gundi from North 

 Africa, on the borders of the Sahara. Has no premolars ; each foot 

 has four digits ; the hind limbs are rather longer than the fore ; the 

 ears small ; and the tail reduced to a stump. This animal is about 

 the size of the Water- Vole, and dwells on rocky ground, its habits 



FIG. 213. Skull of Hydrochcerus capybara (reduced). 



being diurnal. The peculiar comb-like inner toes are employed for 

 dressing the fur. 



Pectinator? Closely allied to the preceding, but with a minute 

 premolar in each jaw ; and a moderately long and bushy tail. One 

 species (P. spekei), from Somali-land. 



Subfamily Oetodontinse. Molars semi-rooted or rootless, with 

 simple enamel-folds ; fur soft. There are some six existing genera, 

 including Rat-like species, all of which are South American, except 

 Petromys, which is Ethiopian. 



Octodon. 3 Upper and lower molars alike ; ears moderate ; tail 

 of medium length and tufted. Vertebrae : C 7, D 1 2, L 7, S 4, C 

 25. Typically represented by C. cumingi of Chili and Peru, with 

 other species from Chili and Bolivia. They live in large com- 

 munities. 



1 Gray, Spicilcgia Zoologica, p. 10 (1830). 



2 Blyth, Journ. As. Soc. Bengal, vol. xxxiv. p. 294 (1855). 



3 Bennett, Proc. Zool. Soc. 1832, p. 46. 



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