214 Bulletin American Museum of Natuial History. [Vol. V, 



though clothed with very short dusky hairs, generally not readily seen without 

 a lens. 



Measurements, from fresh specimens: Total length, 271 mm.; head and 

 body, 123 ; tail, 148 ; hind foot, 25 ; ear above crown, 16. 



Skull similar to that of the preceding species, except that the nasals and the 

 facial portion of the skull are much longer and the interparietal much smaller. 

 In old skulls the supraorbital ridge is continued backward to the posterior border 

 of the parietals. Total length, 32.5 ; basal length, 27.2 ; greatest zygomatic 

 breadth, 17.8 ; greatest mastoid breadth, 12 ; least interorbital breadth, 6.1 ; 

 length of nasals, 11.4 ; antero-posterior breadth of interparietal, 3.5 ; transverse 

 breadth of same, 9.3 ; length of anterior palatine foramen, 6.4 ; greatest width 

 of same, 2 ; distance between incisors and first molar, 8.4 ; length of crown 

 surface of upper molar series, 4.5 ; length of lower jaw, 20.3 ; height at condyle, 

 8.6. 



Type, No. ffff, 3 ad., Princestown, Trinidad, April 25, 1893, coll. Frank 

 M. Chapman. 



This species is based on three specimens, a very old male and 

 an old female, and a young adult male. The very old specimens 

 are closely similar in all features ; the younger specimen, although 

 practically adult as regards size, is less rufous and more yellowish 

 above and rather more whitish below, with the throat pure white 

 to the base of the fur. 



This species differs from the preceding in the character of the 

 pelage, in coloration, especially of the lower parts, in being larger 

 and with a relatively longer and less hairy tail, and in various 

 cranial differences, particularly in the much shorter interparietal. 

 What its nearest relative may be among the continental species it 

 is impossible to decide in the absence of proper material for 

 comparison. 



15. Oryzomys velutinus, sp. nov. 



Pelage thick, short (about 7 mm. long on the back), velvety below. General 

 color above dark cinnamon-brown, darkest and much mixed with blackish on 

 the middle of the back, lighter and more reddish on the sides, brighter reddish 

 on the hinder part of the crown and posteriorly over the shoulders ; anterior 

 part of the head dusky grayish brown with only a faint tinge of reddish, and a 

 narrow, indistinct blackish eye-ring ; beneath grayish white at the surface, 

 dusky plumbeous basally. Ears large, broadly oval, naked on both surfaces, 

 dusky with a faint reddish cast. External surface of the limbs like the adjoin- 

 ing portions of the body ; feet thinly haired above, yellowish gray, this color 

 extending on the hind feet to slightly above the ankles ; palms and soles naked, 



