582 
PROCEEDINGS OF THE NATIONAL MUSEUM, 
VOL. xxxii. 
oremispinw. It is possible that two or more species of the. genus 
Acanthion are found on Borneo; but at present there is nothing in the 
literature to show this fact satisfactorily or to indicate what their 
characters are. 
THECURUS, new genus. 
Family. —Hystricidir, subfamily Hvstricimv. 
Tyi re.—Theeurus sumatrse^ new species. (Description on page 583.) 
Species, —The type species is the only known one in the genus so far 
as known. 
Diagnostic characters, —External ] y like a small Acanthion , but cap¬ 
sule'! ike ends of caudal hairs, smaller and relatively shorter, often 
closed at the ends (Plate LV11, fig. 2), quills smaller, and replaced on 
lower rump by grooved spines similar to those on upper back. Crani- 
ally very similar to the genus Atherurus, but brain-case relatively 
wider, rostrum narrower, and no well-marked fossa on outer side of 
mandible just beneath condylo-coronoid notch; molars rootless. 
External characters*— About half the size of Acanthion, to which it 
has a striking resemblance, but it has no bristly hairs on the head or 
neck, but merely soft, flattened spines. The flattened spines extend 
farther down the back than they do in Acanthion and are mqfe con¬ 
spicuously grooved, and they are also found on the lower back and 
rump instead of the short quills of Acanthion . The large heavy 
quills occupy about the third fourth of the hack. They are much less' 
numerous and shorter than those of Acanthion. , the largest not exceed¬ 
ing 150 mm. These quills are dark in color, with a light lni.se and 
apex. A very few long slid bristles are interspersed among the quills. 
Some short quills are found on the base of the tail, while the terminal 
portion of that organ is covered with peculiar modified hairs, but (he 
capsules are relatively much shorter and a great many more of them 
are closed at the apex—drawn out to a point. (Plate LVII, lig, 2.) 
The sides of the head, the underparts, and the legs, are in general 
clothed with rather soft, flattened, grooved spines. 
Skeleton. —The main features of the skull of the genus Theeurus 
have previously been pointed out. The relative size and shape of the 
skull and its various parts are clearly shown in lig, 1. Plates LIV, LV, 
and LVI, so that no detailed description is here necessary. The verte¬ 
bral formula is: Cv. 7, D. 14, L. 5, 8. 4, Cd. 17. Although the skele¬ 
ton of Theeurus as a whole, aside from the skull, is in general strikingly 
like that of Acanthion, yet in one or two points it is quite different. 
Instead of having a large, laterally compressed neural spine on the 
axis, that vertebra bears a relatively short, t-ri-prismatic spine, not com¬ 
pressed laterally any more than it is antero-posteriorly. (Plate LVII, 
fig. 9.) The seventh cervical vertebra in Theeurus has no long neural 
spine. The long neural spine on the seventh cervical seen in Acan- 
