NO. 5 MAMMALS OF PANAMA GOLDMAN IO5 



the result being a more complicated enamel pattern than in Ory::omys. 

 Some of the South American species of Nectomys are the largest 

 American Murine rodents. 



NECTOMYS ALFARI EFFICAX Goldman 

 Cana Rice Rat 

 [Plate 23, figs. 6, 6a] 

 Nectomys alfari efRcax Goldman, Smiths. Misc. Coll., Vol. 60, No. 22, p. 7, 

 February 28, 1913. Type from Cana, eastern Panama (altitude 1,800 

 feet). 



Nectomys a. efficax is a richly colored, long-haired animal belong- 

 ing to the section of the genus including rather small species — 

 N. esmeraldarum and others — which lack the fringed feet and toes 

 of the more typical Nectomys squamipes group. In the more essen- 

 tial characters, however, the two groups are closely congeneric. 

 N. a. efficax is closely allied to N. a. alfari ' of Costa Rica. It differs, 

 however, in the richer, more tawny ochraceous coloration of the 

 upperparts and the skull has a narrower braincase and more massive 

 rostrum. It is somewhat similar to N. esmeraldarum, but larger, 

 the color paler, more ochraceous, and the skull more elongated. 

 N. dimidiatus of Nicaragua is a much smaller species with a different 

 skull. 



This rice rat is one of the more common Murine rodents in the 

 grassy clearings, old cane fields and second growth forest at i,8oo 

 to 2,000 feet altitude on the small plateau commonly known as the 

 Cana Valley. It was especially abundant in the rank grass growing 

 on the marshy valley bottom. No examples were taken in the heavy 

 forest. In examining specimens in the flesh it was noted that the 

 number of tubercles on the sole of the hind foot is variable. In some 

 examples there are five with no trace of a sixth ; in others six are 

 distinctly shown, but the postero-external may be very small ; in still 

 others the small sixth tubercle is present, but very minute on one foot 

 and absent on the other. Anthony (1916, p. 369) found the Cana 

 rice rat common at 2,650 feet at the village of Tacarcuna, but it 

 " strangely was not taken elsewhere." 



Specimens examined: Cana, 33; Tacarcuna, 15.- 



^This species was described as the type of a new genus, Sigmodontomys 

 Allen (Bull. Amer. Mus. Nat. Hist., Vol. 9,'p. 39. March ir, 1897), which is 

 clearly identical with Nectomys Peters. 



'Collection Amer. Mus. Nat. Hist. 



