On new Forms of Nasua and Dasyprocta. 271 
5. The Pinguipedids, with the single genus Pinguipes, 
agree in all respects with the preceding, but as they lack the 
subocular lamina they should be regarded as a distinct family. 
P. chilensis has 38 vertebre (17+ 21). These fishes bear a 
certain resemblance to the Labrid Malopterus, C. & V. (Neo- 
labrus, Stdr.), the skeleton of which is still unknown; but 
its ally Ctenolabrus has 15-17+18-19 vertebrae, which is 
very near the number in Pinguzpes. 
XXXVIT.—New Insular Forms of Nasua and Dasyprocta. 
By OLDFIELD THOMAS. 
WHEN examining material in connexion with the new forms 
of Nasua described last month, the specimens from Cozumel 
Island in the Bay of Honduras struck me as peculiar, and 
now that the skulls have been prepared I find that this 
animal should be distinguished from that on the mainland. 
As I am responsible for its determination as N. nasica (see 
P. Z. 8. 1888, p. 129), or narica, as I prefer now to call it, 
I think it well now to set the matter right, and also to point 
out that another identification made at the same time was 
erroneous, that of the Agouti from Ruatan, which likewise 
proves separable from its mainland ally. 
Nasua thersites, sp. n. 
Size markedly less than in the continental N. narica. 
General colour of head, nape, and posterior back dark brown 
(“seal-brown’’), only grizzled across the shoulders, where 
the tips of the hairs are whitish or ashy. Continental 
specimens are usually grizzled further down the back. Bases 
of the brown hairs but little lighter than their tips. Under 
surface brown posteriorly on the belly, grizzled with whitish 
on the chest; the chin white. Face, as usual, brown, with a 
white muzzle and lips, white spots above and below the eye, 
and whitish lines leading from the eyebrows to the muzzle. 
Patches on sides of neck whitish, the hairs brown basally. 
Ears brown externally, white internally and at their edges. 
Limbs brown, darkening nearly to black on the hands and 
feet. Tail shaggy, dark brown throughout, slightly darkening 
terminally, without trace of grizzling or annulation. 
General build of skull distinctly that of the N. narica type 
and quite different from that either of the delicate VV. mon- 
tana and guichua or of the still slenderer NV. olivacea, although 
