118 Mr. E. E. Alston on Perognathns bicolor of Gray. 



EXPLANATION OF PLATE III. 



Gastrosaccus spiniferus. 



D, dorsal view. C, cephalon, showing rostrum and 



L, lateral view. frontal process, with the eyes. 



T, telson. prp. 5, penultimate pereiopod. 



a. s., upper antenna. pip. 1, first pleopod. 



a. »., lower antenna. pip. 2, second pleopod. 



sc, scale of lower antenna. car., lateral view of dorsal spines 



l, labrum, with palps of mandi- of carapace, 



bles. Is., life size. 



XIV. — Note on the Perognathns bicolor of Gray. 

 By Edward E. Alston, Sec. L.S. 



Twelve years ago the late Dr. J. E. Gray described a Pero- 

 gnathus bicolor from Honduras*. He stated that it was 

 black above, with uniform bristly fur, and gave the habitat as 

 "Honduras (Salle)," adding "There is a spiny rat from 

 Honduras with a longer tail and smooth front teeth, agreeing 

 in colour with the above." 



In 1876, when writing to my friend Dr. Elliott Coues on 

 the United-States specimens of Geomyidae in the British 

 Museum, I made the following casual observation on this 

 species, which I did not suppose would have come within the 

 limits of the l Monograph of the North-American Eodentia,' 

 but which he included with the quotation from my letter : — 

 u P. bicolor, Gray (from Honduras), appears to be a good 

 species, but has been curiously badly described. It is dark 

 brown above, not black ; and though the fur is sparse and 

 somewhat harsh, it is not in the least bristly ! Gray seems to 

 have had both this specimen and his Heteromys melanoleucus 

 in his hands when he wrote, and to have confused one with 

 the other " t- 



Having since had occasion to revise the species of this 

 family, I find that I had greatly underrated the depth of error 

 into which Gray had sunk on this occasion. Mr. Oldfield 

 Thomas has drawn my attention to the fact that the frag- 

 mentary skull of the type specimen is preserved, under its 

 old misnomer of Perognathus monticola ; and this proves that 

 the animal is a Heteromys, perfectly identical with Gray's 

 " spiny rat with smooth front teeth." Moreover, by a refe- 

 rence to the original registers, Mr. Thomas finds that these 

 specimens were not sent by Salle from Honduras, but by 



* P. Z. S. 1868, p. 202. 



t Mon. N.-Am. Rodent, p. 515. 



