2 1 8 Bulletin American Museum of Natural History. [Vol. V, 



give the following dimensions : Total length, 192 (188-196) 

 mm. ; head and body, 123 (121-125) ; tail, 69 (65-70) ; hind foot, 

 24.6 (23-27) ; ear from crown, 13 (12-15). The dental and 

 external characters agree with Waterhouse's diagnosis of his 

 subgenus Abrothrix. 



This species, with Loncheres, was the only one of the Muridae 

 or Octodontidae which seemed to be diurnal in its habits. Their 

 appearance in life suggests that of an Arvicola. 



18. Mus rattus Linn. A single specimen was captured at a 

 neighboring cacao estate, and was the only one observed. 



19. Mus alexandrinus Geoff r. Common in the vicinity of 

 houses, and on two occasions captured at a small uninhabited 

 palmetto thatch in a forest. 



20. Mus musculus Linn. Common at Port-of-Spain, and 

 probably occurs throughout the island. The presence of cats 

 and dogs at the rest-house doubtless prevented the occurrence 

 there of either of the three species of Mus. 



21. Heteromys anomalus (Thompson]. This species was 

 originally described by Thompson in 1815,' from a single speci- 

 men from the island of Trinidad. Few examples appear to have 

 as yet fallen into the hands of naturalists, and even the people of 

 Trinidad are almost unaware of its existence. According to Mr. 

 Oldfield Thomas (Journ. Trinidad Field Nat. Club, I, 1892, p. 

 165), the type and one other specimen, the latter received in 

 1891, are in the collection of the British Museum. It is therefore 

 gratifying to report that the present collection contains a series 

 of 30 specimens, including five in alcohol. Both sexes and all 

 ages are represented, from the suckling young to aged adults. 

 From this material the species may be redescribed as follows : 



Adult. Above grayish dusky brown faintly washed with chestnut ; below 

 pure white to the base of the hairs. The dark color of the upper surface is 

 sharply defined against the white of the lower surface, without any trace of the 

 fulvous lateral line seen in most of the northern species. Outer surface of the 

 fore and hind limbs like that of the adjoining portions of the body ; inner 

 surface white, except that the dusky color of the outer surface completely 



1 Trans. Linn. Soc. London, XI, 1815, p. 161, pi. x. 



