kukenthal: astylosternus robustus. 3/3 



of the same size with very short appendages. I find no males without 

 these villosities, for even the smallest male at my disposal possesses 

 them. 



It is to be regretted that the collector of these specimens, Mr. 

 Schwab, has not given any notes about the time of year when he cap- 

 tured the different specimens; but, notwithstanding this, we can draw 

 with almost absolute certainty the conclusion that these appendages 

 are much more highly developed at one time of year than at other 

 times. Moreover it is very probable that this time corresponds with 

 the breeding period. Direct observations, of course, would quickly 

 settle this question. 



The fact that a younger (smaller) male, contained in the same jar 

 with the two adult males possessing fully developed appendages — and 

 therefore apparently captured at the same time with these — showed 

 this hairy coat in its beginnings, points to the conclusion that the 

 appendages are fully developed only on adult animals, and probably, 

 as I have already suggested, at the time of mating. 



Now arises the question, from what do these organs originate? 

 The reply recjuires a careful investigation of the female (Plate 5). 

 It is quite surprising, that none of the former investigators has ob- 

 served the fact, that the females have, on exactly the same parts of 

 the body that on the males bear these appendages, small but quite 

 distinct tubercles, which have the same diameter as the bases of the 

 appendages in the male. Their distribution over exactly the same 

 areas of the surface shows clearly that they are homologous with the 

 appendages of the males. 



Moreover, if we carefully study the surface of the skin (Plates 1, 3-5), 

 we find that both males and females show similar tubercles scattered 

 over the whole back, and that they are more closely crowded in the 

 region of the angle of the jaws (Plate 3). In some areas of the surface 

 of males we may even observe the transition of these tubercles into 

 the villous appendages. From these comparisons we must therefore 

 draw the conclusion that these appendages have originated from 

 tubercles of the skin, such as we find scattered over the skin of this 

 species in other regions of the body and such as are recorded from other 

 species of Ranidae. 



These hair-like appendages are therefore to be considered as highly 

 developed tubercles of the skin. 



I have studied the microscopical structure of these appendages in 

 series of sections, which Mr. S. Kornhauser has been kind enough to 

 prepare. The stains which were used were : borax-carmine and bleu de 



