CASTOR 949 



and more curved, tliat of fourtli digit with a conspicuous, horny, 

 laterally-conijjressed supplement fully as large as claw itself 

 spi'inging from ball of finger beneath claw ; entire sole naked, 

 tlie surface coarsely reticulate ; three elongate, ill-defined pads 

 at base of median digits, a larger and better-defined tubercle 

 behind base of hallux ; entire sole between hallucal tubercle and 

 heel thickened and pad-like. Tail furred at extreme base, the 

 scales of naked portion wider than long, 4-G-sided, about 100 

 in longitudinal series, forty in circumference, those on lower 

 side somewhat larger and better defined than those on upper 

 side. Fur consisting of dense soft under portion, the hairs of 

 which are about 25 mm. in length, and an abundant growth of 

 rather coarse stiff longer hairs (50 to 60 mm.) nearly concealing 

 the underfur. 



Colour. — General colour a peculiar clayey buff produced by 

 the longer hairs, and very uniform throughout, the nnderparts 

 a little less yellowish ; underfur light smoke-grey at base, 

 darkening to hair-brown or bister at tips, this colour rarely 

 showing thi-ough at surface ; muzzle, chin, and lower part of 

 cheeks greyish but not forming any decided contrast with 

 surrounding parts ; feet washed with a drab brown. 



SJiull. — In general aspect the skull is low, robust and heavily- 

 built, though not con.spicuously ridged and furrowed, and not 

 noticeably widened ; the broadly expanded malar is a conspicuous 

 feature in lateral view. Dorsal profile moderately and irregularly 

 convex, usually with a flattened or slightly concave area between 

 orbits and another just in front of lambdoid region ; occiput 

 squarely truncate or somewhat overhanging, the condyles barely 

 or not visible when skull is viewed from above ; ventral profile, 

 owing to depth of rostrum and shallowness of brain- case not 

 diverging conspicuously in general direction from dorsal profile 

 except for the projection formed by the tooth-row and by the 

 auditory bulla. Brain-case rather narrowly ovate in general out- 

 line, its breadth over roots of zygomata contained about 1^ times 

 in length ; meatal tubes of auditory bulkw standing out con- 

 spicuously just in front of mastoid protuberances and rising to 

 level of dorsal surface of brain-case ; sagittal crest moderately 

 developed in adults, highest posteriorly, dividing anteriorly into 

 two low ridges curving forward and outward to rudimentaiy 

 postorbital processes ; lambdoid crest well developed, sloping 

 backward ; occiput low and broad, somewhat quadrate in outline 

 when viewed from behind, scarcely exceeded in height by middle 

 portion of brain-case, its median height slightly more than half 

 its greatest width, its surface with no special features ; par- 

 occipital process short and robust, not extending to level of 

 lower lip of foramen magnum ; floor of brain-case with deep pit 

 occujiying entire area between bullae, its edges well defined 

 throughout, its posterior margin formed by lower lip of foramen 

 magnum ; auditory bulla flask-sha^jed, the meatal tube about as 



