1936] Halt, Hyraxes Collected by American Museum Congo Expedition 131 



this area there are periods focussing in January and July in which the 

 rainfall is slightly lighter than in the balance of the year, but the differ- 

 ence is small and the " seasons" short, with the result that pelage changes 

 are not known to occur in response to the little seasonal change. The 

 skins of this series were critically examined with reference to any such 

 possible change, but none was found. 



Many specimens in the collection have a reddish-yellow tinge, par- 

 ticularly marked on the lighter underparts, that is due either to a soil- 

 ing in the original environment or to changes occasioned by grease in- 

 completely removed from the study skin. A vigorous application of 

 benzine serves to remove much of this color, but some of it, which I 

 assume to be natural to the hair, remains. One striking example of a 

 hyrax with a coloration that suggests staining, yet proves non-remov- 

 able, is the yellow-banded individual (No. 53819) pictured in Plate XX. 



Attainment of Full Growth 



There is a range in total length of specimens with skulls in Stage 

 VIII from 525 mm. to 625, with the individuals scattered fairly uni- 

 formly between these extremes. The four with skulls in Stage VII also 

 lie within these limits, the lower limit coinciding with that of Stage VIII, 

 the higher limit lying at 535 mm. Two specimens in Stage VI are 525 

 and 545 mm. long, and the one individual in Stage V, is 550 mm. long. 

 It would thus appear that full growth in this species is attained at 

 about Stage V, though the greater upper range limited to Stage VIII 

 suggests a continuation of growth after Stage VIII is first attained. 

 The one specimen in Stage IV and the one in Stage III are 465 and 460 

 mm. long, respectively, which is distinctly smaller than any of those in 

 Stages V to VIII. 



Behavior 



Field notes made by Mr. Lang at Ngayu on December 19, 1909, 

 Medje, January 22, 1910, and Gamangui, February 18, 1910, shed some 

 light on the habits of the species. These notes combined for brevity and 

 slightly altered in wording where necessary, are as follows : 



General Behavior. — A male brought in alive by the pygmies, moved very 

 slowly on the ground when undisturbed, but would rush rapidly for a yard or two 

 towards a stick thrust at it, or a person that would approach. At such times it would 

 turn its eyes so far backwards that only the yellowish white membranes in front or 

 in back could be seen, and would also erect the hair along its back and that on its 

 head. This little beast understands how to command the respect of all. 



