158 RICHARD EVANS. 



In the second place, do the specimens with from twenty- 

 four to twenty-eight pairs of appendages (P. gnianensis) 

 from tlie Demerara belong to the same species as the 

 individual Avith twenty-seven pairs from the Pomeroon 

 referred by Mr. Sedgwick to V. d em era ran us (P. im- 

 Thurmi, Sclater) ? Although the supposition that the 

 material from these two localities mentioned in the above 

 question belongs to the same species seems legitimate, I do 

 not consider it very probable. In discussing this question it 

 should be remembered that Mr. Sedgwick saw Mr. Sclater's 

 specimens alive, opened them, and took the embryos out of 

 them; and although he was "unable to mnke a detailed 

 examination of them in the fresh state," I am fully convinced 

 that if the individual possessing only twenty- seven pairs of 

 appendages had displayed the same characteristic markings 

 as P. gnianensis does, he would have immediately detected 

 the difference between it and the remaining nineteen speci- 

 mens of the collection in question. The most likely view 

 seems to be that Mr. Sedgwick examined two species which 

 could not be distinguished from each other with the naked 

 eye, unless the appendages were counted a feature, to which, 

 at that time, no great importance was attached. It is un- 

 fortunate that so little is known of the structure of the 

 specimen possessing twenty-seven pairs of appendages from 

 the Pomeroon, and the only correct attitude, until a further 

 supply from that district shall have been collected, is to 

 suspend judgment. Owing to this uncertaintj^ I prefer using 

 a new name, gnianensis, to adopting the invalidated one, 

 demeraranus, for the new species described in the present 

 paper. 



