1908.] Alltn, Mammals from Nicaragua. 655 



28. Oryzomys couesi Thomas (ex Alston). Twenty-nine specimens, 

 of which 23 are from Chontales, Feb. 8-28, 1908; 2 from Ocotal, May 4 

 and 11, 1908; 1 from San Rafael del Norte, April 12, 1907, and 3 from 

 Tuma, Nov. 3, 23, and 24, 1907. 



These specimens agree satisfactorily with Thomas's redefinition l of 

 O. couesi (type locality, Coban, Guatemala). The coloration above is 

 fulvous, finely lined with black on the back, which is thus somewhat darker 

 than the sides; below buffy white. Very old specimens are brighter colored, 

 tending to rufous on the lower back and to strong buff below. Ten of the 

 oldest specimens of the series (judging by the skulls) measure (collector's 

 measurements), total length, 268 (260-280); tail, 136 (130-140). Basal 

 length of skull, 27.5-29.5; nasals, 11-11.6; width of braincase, 12.2-12.7. 



This species has apparently a wide range, from the low Atlantic coast 

 district (altitude 500 to 1000 feet) to the highlands (altitude 4000 to 5000 

 feet) of the central part of the Republic, specimens from the latter district 

 being in no way distinguishable from those from the former. 



29. Oryzomys alfaroi Alien. Nine specimens: Chontales, 6 specimens, 

 Feb. 13-25, 1908; Tuma, 3 specimens, Nov. 15-18 and 25, 1907. 



These specimens are indistinguishable from the type and topotypes of 

 the species, from San Carlos, Costa Rica. 



30. Oryzomys alfaroi incertus subsp. nov. 



Type, No. 28584, tf ad., Rio Grande, March 28, 1908; W. B. Richardson. 



Differs from 0. alfaroi alfaroi in smaller size, darker back, and golden rufous 

 instead of pale fulvous suffusion of the upper parts. Total length (type), 190 mm.; 

 tail. 100. Two other specimens measure, respectively, total length 190 and 200; 

 tail, 100. Five specimens of alfaroi from Chontales measure, total length, 210 

 (200-220); tail, 106 (100-110). The skulls are badly broken, lacking the occipital 

 portion, but so far as they can be compared appear to present no distinctive features. 



31. Oryzomys ochraceus sp. nov. 



Type, No. 28548, <? ad., Rio Grande, Nicaragua, March 27, 1908; W. B. Rich- 

 ardson. 



Pelage very thick, long and soft. Upper parts ochraceous, somewhat darker 

 on the back by the admixture of black-tipped hairs, and brighter on the flanks; 

 top and front of head not darker than the body; under parts strongly washed with 

 buff or pale yellow; ears dark brown, naked; upper surface of fore and hind feet 

 dingy grayish brown; tail uniform dark brown throughout, not lighter below, naked 

 in sume specimens, in others with very short fine hairs, not concealing the annulations. 



Total length (type), 300 mm.; tail, 180; hind foot, 40 (collector's measurements). 



i Ann. and Mag. Nat. Hist. (6), Vol. XI, May, 1893, pp. 403, 405. 



