1934] Hatt, American Museum Congo Expedition Pangolins and Aard-Varks 657 



hair is that of the orbital ring. By the time the animal is half grown the 

 unsealed parts of the skin are covered with a sparse growth of short, light- 

 colored hair. The usual course of development is that the hair becomes 

 increasingly dense and long, attaining a length of 20 mm. over the ab- 

 domen. Some areas, few of which are constant, become a Vandyke 

 brown. The hair of the arms on adults is always colored in this manner 

 and any other section may be so. Frequently the sides of the face, the 

 rear legs, and the perineal region are suffused with this color and the throat 

 and belly blotched with it. 



Individual Variation. — Individual variation in length and color 

 pattern of the hair is treated in the paragraph above. Variation in 

 color of the scales appears to be little subject to random variation, 

 though occasional specimens show a few unpigmented scales on the 

 sides of the body and on the tail, which are probably not post-mortem 

 changes, since they are seen in an embryo in alcohol. Scale counts of the 

 transverse longitudinal body rows, of marginal and median caudal scales 

 have been recorded by Frechkop and earlier writers. Ten specimens 

 selected at random, with equal distribution among the sexes, show the 

 following variation in count. My findings are followed in parentheses 

 by the corresponding figures summarized in Frechkop. It is shown by 

 my count that variation within one district is great enough to indicate 

 that scale counts can be of little or no service in recognition of the source 

 of any specimen of the species. 



Number of pre-caudal median scales 27-30 



Number of median bodj' scales 19-21 (18-22) 



Number of longitudinal rows 21-25 (19-23) 



Number of marginal caudal scales 35-40 (34-38) 



Number of median caudal scales 29-36 (30-33) 



Sex Differences. — I am unable to discover external differences 

 between the male and female tricuspis other than those of the sex organs 

 and the lacteal apparatus. The males grow to greater length, as may be 

 seen from the summary of the collector's measurements. The slight 

 difference between the ratio of tail to head and body length obtained 

 from these figures (6 71 168 per cent- 9 166 per cent) is almost certainly 

 of no significance. 



Geographical Variation. — As suggested above, the external differ- 

 ences between members of this species from different localities seem to be 

 inconstant, and whereas I am of the opinion that the animals from 

 opposite extremes of the range present divergent tendencies, I have not 

 found a single character which may be relied upon to differ in a constant 



