498 Mr. 0. Thomas on some 



six plantar pads, while, so far as T know, all the other species 

 have only five. 



In Trinidad there occurs N. palmipes. All. & Chapra., 

 whose skull may be distino^uislied by the much more uniform 

 breadth and more abrupt ending behind of the nasals. 



Thirdly, of described species, there is N. apicalis, Peters *, 

 described from Guayaquil, wliich has particularly long narrow 

 nasals, tapering behind to a long drawn-out point. This 

 species I have also recorded from Cliirimoto and Araable 

 Maria, Peru. 



Besides these three species, the Museum possesses speci- 

 mens of three more, each re])resentative of a distinct geogra- 

 phical district, and eacli distinguishable by cranial characters. 

 No doubt all six species are very closely allied, but, so 

 far as the material goes, the species seem to be quite constant 

 in the characters used. 



The first species is from the valley of the Cauca, and has 

 elongate and broad nasals, straight supraorbital ridges, and a 

 flattened frontal region. This is the largest species as yet 

 known, and may be called N. grandis. 



The second is from the Magdalena Valley, and may be 

 called N. niogdalence. Its skull is much more rounded, both 

 on forehead and brain-case, than usual, and contrasts in this 

 respect with the other species, which are all flattened in the 

 frontal region. 



Lastly, there is a species, believed to be from Quito, which 

 is distinguished from all tlie rest by its rich fulvous colour. 

 In the skull it has a much flattened frontal region, of which 

 the bounding ridges are straight and less divergent than 

 usual. It may be called Nectomys fulvinus. 



The following are the detailed descriptions of the three new 

 species : — 



Nectomys grandis y sp. n. 



Size large. General colour coarsely mixed black and dull 

 yellow, the resulting tone not unlike that of N. squamipes, 

 although the mixture is rather coarser. Sides dull brownisii 

 yellow, gradually passing into the yellowish buff of the belly. 

 Belly hairs slaty grey basally, as usual. Hands and feet dark 

 brown, edged with closely-set whitish bristles; soles naked, 

 scaly, with five pads, all rather larger than in N. apicalis, 

 especially the large ])roximal one, which is both longer and 

 broader than in the allied species. Tail long, coarsely scaled, 

 uniformly blackish, the under surface with a few whitish hairs 

 intermixed with tlie black. 



♦ Abh. Ak. Berl 1860, p. 152. 



