768 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.xxiv. 
Tdll. — The tail is distinctly annulated. At middle there are about 
ten rings to the centimeter. The boundaries of the scales are sharply 
defined, nuich more so than in Mus stoiciis and Mus jlebilis. From the 
base of each scale grow three hairs which in length are equal to the 
width of two rings. Though better developed than in the larger 
Andaman rats, these hairs do not conceal the annulation of the tail. 
Feet. — The feet are in no way peculiar. Soles naked, 6-tuberculate. 
Ears. — The ears are of moderate length, about ecjual to distance 
between e3"e and nostril. They are naked except for a fine, incon- 
spicuous pubescence. 
Skull. — The skull is nuich like that of Mu^i rattus, except that the 
frontal profile is more strongly concave, the audital bullae are smaller, 
and the region between and including anterior zygomatic roots is 
broader and more heavily built. The incisive foramina extend back 
nearl}^ to level of middle of first molar. 
Teeth. — The teeth are similar to those of 3his rattus but very much 
larger. 
Measurements. — External measurements of type: Total length, 342 
mm.; head and body, 160; tail, 182; hind foot, 36 (34); ear from 
meatus, 18; ear from crown, 14; width of ear, 13. Average of seven 
adults from the type locality: Total length, 353 (342-372); head and 
body, 175 (160-195); tail, 181 (173-190); hind foot, 39.7 (39-41.6); 
hind foot without claws, 37.3 (36-39). For detailed measurements 
see table, page 772. 
^Specimens examined. — Eight, all from the type locality. 
Reniarhs. — In the appendix to Mouat's Adventures and Researches 
among the Andaman Islanders Blyth remarks that — 
lately the Rev. C. S. P. Parish, the able botanist and chaplain of Moulmein, 
observed on Barren Island the half-devoured remains of some rat, which it is not 
likely had been carried by a bird of prey from the nearest land, 36 miles distant. 
As the carcass was much mutilated, Mr. Parish did not think it worth while to pre- 
serve it in spirits, though had he done so the identification of the species, with the 
peculiar spiny-coated Mus andamanensis, would probably have been easy. 
This is the only published allusion to the Barren Island rat that I. 
have seen. 
Dr. Abbott foimd the animal excessively abundant in favorable 
localities among the patches of grass and scrubby jungle with which 
the volcanic ash and scoria of Barren Island are covered. He noted 
nothing peculiar in its habits. 
MUS BURRUS, new species. 
Type.— Adult female (skin and skull). No. 111811, U. S. N. M. Col- 
lected on Trinkut Island, Nicobars, February 5, 1901, by Dr. W. L. 
Abbott. Original number, 881. 
