NECTOMYS. RHEOMYS. 55 



Color. Orbital ring and spot at base of whiskers dusky; upper- 

 parts Mars-brown; dorsal area darkest; underparts yellowish white; 

 tail blackish above and below; hands and feet white, tarsal joint brown- 

 ish. Ex type in United States National Museum. 



Measurements. Total length, 219; tail, 116; hind foot, 21 (skin). 

 Skull: Occipito-nasal length, 32.6; Hensel, 25; zygomatic width, 16; 

 in tertemporal width, 5.3; length of nasals, 12.3; length of upper molar 

 series, 5.3. Ex type in United States National Museum. 



Genus Nectomys Peters. 



Nectomys Peters, Abhandl. K.. Preuss. Akad. Wiss. Berlin, 1860- 



61, p. 151. Type Mus squamipes Lichtenstein. 

 Nectomys dimidiatus Thomas. 



Nectomys dimidiatus Thomas, Ann. and Mag. Nat. Hist., Ser. 7, 

 XVII, 1906, p. 422. 



Type locality. Escondido River, 7 miles below Rama, Nicaragua. 



Nectomys alfari efficax Goldman. 



Nectomys alfari efficax Goldm., Smith. Misc. Coll., LX, 1913, No. 

 22, p. 7. 



Type locality. Cana, eastern Panama. Altitude, 1,800 feet. 



Genl. Char. Similar to N. alfari, but more tawny-ochraceous. 

 Skull with narrower braincase and rostrum heavy. 



Color. Upperparts pale tawny-ochraceous and black; top of head 

 and face darker; flanks and outer side of limbs have the ochraceous 

 color predominating; underparts washed with pale buff over white; 

 tail brownish all around; hands and feet flesh color sparsely covered 

 with gray hairs. Ex type in United States National Museum. 



Measurements. Total length, 305; tail, 179; hind foot, 36.5. 

 Skull: Occipito-nasal length, 35.6; Hensel, 28; zygomatic width, 

 19.7; intertemporal width, 7.2; length of nasals, 14.2; length of upper 

 molar series, 5.4; length of mandible, 18.9; length of lower molar series, 

 5.5. Ex type in United States National Museum. 



Genus Rheomys. 



Rheomys Thomas, Ann. and Mag. Nat. Hist., Ser. 7, XVII, 1906, 

 p. 421. Type. 



Rheomys underwood! Thomas. 



Rheomys underwopdi Thomas, Ann. and Mag. Nat. Hist., Ser. 7, 

 XVII, 1906, p. 422. 



