658 Bulletin American Museum of Natural History. [Vol. XXIV, 



33. Ototylomys fumeus sp. nov. 



Type, No. 28291, c? ad., Matagalpa, Nicaragua, March 18, 1907; W. B. Rich- 

 ardson. 



Above dusky gray brown, darkening on the middle of the back to blackish brown; 

 below pure white, the pelage short, thick and soft; outside of limbs like the dorsal 

 surface, as far as the base of the toes, which are whitish with a dusky spot at the 

 base; inside of limbs pure white to the base of the toes; ears dusky brown, apical 

 three-fourths naked, not larger than is usual in Neotoma; tail naked, the scales large 

 and smooth, black, slightly lighter on ventral surface. 



Total length (type), 330 mm.; tail vertebrae, 140; hind foot, 30 (collector's 

 measurements). Four adult specimens (1 cT, 3 9) measure: Total length, 320 

 (300-330); tail, 148 (140-170 only one 170). Skull (type, tf), total length, 42; 

 condylo-basal length, 38; zygomatic breadth, 21; length of nasals, 14. An adult 

 female, total length, 42; condylo-basal, ; zygomatic breadth, 21.5; nasals, 15. 

 (The five other skulls are too much broken or are too immature for measurement). 



Represented by 7 specimens, of which 4 are fully adult with worn teeth, the 

 others immature. The half-grown young are dark grayish brown above, heavily 

 washed with black; below white. Five were taken at Matagalpa, one at Ocotal and 

 one at Volcan de Chinandega. It thus appears to range from about 4000 to about 

 6000 feet. 



This species is much larger than the other known forms of the genus 

 (from Yucatan and Campeche), with a relatively shorter tail, smaller ears, 

 and absence of fulvous suffusion, the skull being 4 mm. longer, and the head 

 and body about 30 mm. longer than in Ototylomys phyllotis Merriam (type 

 of the genus) from Yucatan, while 0. p. pliceus Merriam, from Campeche, 

 is still smaller. 



In the unworn teeth, both upper and lower, the tubercles of the crown 

 are placed directly opposite, three pairs on m 1, two pairs on m 2, and two 

 pairs on m3, which has a posterior loop in both upper and lower series. 

 When worn down the pattern is much as in Zygodontomys. 



A striking feature of the tail is the great width of the smooth, black 

 annulations, wholly unconcealed by hairs. 



34. Rhipidomys salvinii (Tomes). Two specimens, referred provi- 

 sionally to this species, both taken at Ocotal, in the highlands of northern 

 Nicaragua, Feb. 18 and May 9, 1908; both adult males. They seem to 

 agree in every particular with Tomes's description, based on specimens from 

 Duenas, Guatemala. 



35. Peromyscus nicaraguse sp. nov. 



Type, No. 28282, J 1 ad., Matagalpa (altitude about 4000 feet), Nicaragua, 

 March 10, 1907; W. B. Rchardson. 



Similar in coloration to P. nudipes (Allen) from Central Costa Rica, but wholly 



