6 University of California Puhlications in Zoology [Vol. 21 



furred with hairs the same color as light tipped hairs of upperparts. 

 Tail distinctly bicolor, dark clove brown above and pallid neutral gray 

 below. Hands and feet covered with hairs of a pallid mouse gray 

 color. In worn pelage : Mass effect lighter and more buffy. Light 

 tipped portions of hairs of upperparts almost uniformly cinnamon 

 buff. Some specimens in this pelage are decidedly grayish. 



Skull. — In general form moderately broad, rather deep, with 

 slender rostrum and abruptly spreading zygomata. Dorsal profile 

 rather evenly convex, with region of greatest convexity at interorbital 

 constriction. Occiput somewhat rounded, so that condyles are almost 

 entirely visible when skull is viewed from above. Ventral profile 

 nearly straight, but obliquely sloping from base of incisors posteriorly. 



Fully adult individuals exhibit a subquadrate brain-case, truncated 

 anteriorly by postorbital tuberosities or anteroexternal processes, but 

 these not developed sufficiently to produce a marked break in contour 

 of brain-case. In sexually adult individuals there are faint indications 

 of longitudinal ridges near outer edges of parietals which, though 

 contiguous posteriorly with lambdoidal ridge, tend to disappear ante- 

 riorly on frontals before they join with interorbital ridges. The inter- 

 orbital ridges are not prominent, while sulcus between them is almost 

 closed in old adults. Lambdoidal ridge absent superiorly and repre- 

 sented by outer extremities only. Interparietal somewhat rectangular, 

 with posterior border variable, usually somewhat convex and with 

 outer extremities rather abruptly truncate ; anteroposterior diameter 

 of interparietal, exclusive of m.edian projection, about one-third of 

 greatest transverse diameter. Frontals convex posteriorly and some- 

 what depressed. 



In superior view the slender rostral region tapers gradually to- 

 wards anterior end. Rostrum narrow, scarcely wider at narrowest 

 point behind incisors than interorbital width, the least depth behind 

 incisors somewhat greater than width in same region. Nasals long, 

 spatulate, with anterior declivity very abrupt, widening abruptly 

 slightly anterior to middle, somewhat notched at posterior termination, 

 and rounded. Ascending arm of premaxillae exceeding nasals and 

 extending to or beyond plane of lacrimals. Vertical diameter of open- 

 ing for anterior nares equal to or less than greatest transverse diam- 

 eter. Anteorbital foramen narrow and high, but with superior portion 

 considerably wider than inferior. 



Occiput not depressed, the median depth equalling about 55% of 

 greatest width across lambdoidal ridge of brain-case. Foramen mag- 

 num subtriangular but with more rounded angles. Paroccipital pro- 

 cesses light, directed somewhat downwards and backwards, their tips 

 extending slightly posterior to most projecting point on supra -occipital 

 above foramen magnum. Posterior margins of paroccipitals continued 

 upwards as in aestuarinus, but not so prominent. Basioccipital with 

 a well defined median ridge. Auditory bullae large, abruptly sloping 

 from inner margin to outer, but decidedly depressed in region below 

 meatus. 



Palate with shallow palatine sulci, and slightly elevated median 

 ridge. Lateral bridges not conspicuous. Lateral pits of palate well 

 fenestrated. Interpterygoid fossa about as in aestuarinus, but ptery- 

 goids and hamular processes gradually diverging posteriorly. In- 



