PERIPATUS GUIANENSIS. 157 



That there are two species of Per ipatns inhabiting- the 

 east bank of the river Demerara is an indubitable fact ; 

 namely, P. guianensis, with from twenty-fonr to twenty- 

 eight pairs of Avalking appendages, and another species with 

 thirty-one or thirty-two pairs. No males of the latter species 

 having been discovered, it is impossible to say how many 

 pairs of appendages they possess, but as regards the females 

 it may be stated that, on an average, five out of every six 

 have thirty-one pairs, tlie remaining one being provided with 

 thirty-two. Although over sixty specimens were examined, 

 the majority of which were young, born in captivity, not one 

 of them was possessed of only thirty pairs of legs. If it be 

 taken as proved that there are two species inhabiting the 

 Pomei'oon, the question whether these two species are respec- 

 tively the same as those found on the east bank of the river 

 Demerara immediately suggests itself. 



In the first place, do the specimens with thirty-one or 

 thirty-two pairs of appendages from the Demerara belong to 

 the same species as those with thirty or thirty-one pairs 

 brought from the Pomeroon and examined by Mr. Sclater and 

 by Mr. Sedgwick ? This is a most difficult question to answer, 

 as at present I have no material in hand from the Pomeroon. 

 On the one hand, if we judge from the descriptions and 

 fiofures ofiven of P. im-Thurmi, we should have no hesitation 

 whatever in answering this question in the affirmative ; but, 

 on the other hand, we must take into consideration the very 

 significant fact of the discrepancy in the number of append- 

 ages. Among thirteen specimens of P. im-Thurmi exa- 

 mined by Mr. Sedgwick, seven had only thirty pairs of 

 appendages, six had thirty-one, but none had thirty-two. 

 Among sixty specimens from the Demerara examined by me 

 fifty had thirty-one pairs of appendages, ten had thirty-two, 

 but none had only thirty. In my opinion the complete lack 

 of specimens with only thirty pairs of appendages from the 

 Demerara, and of any with thirty-two pairs from the Pomeroon, 

 are most significant facts, and incline me to believe that the 

 animals under consideration form two distinct species. 



