40 



are rather long, those of the 1st and 4th pairs being twice as long as broad, 

 while those of the 2nd and 3rd pairs are more than two and a half times as long 

 as broad. 



In the largest specimen the carapace is IxV inch long, llf inch broad, and 

 fiths inch deep. 



P. pealianum has been found in Assam and Upper Burma. 



19. POTAMON (PoTAMON) PEALIANUM, var. ANTENNARIUM. 



In this " variety " (using the term " variety " without any impHcation) the 

 antennular fossae are wide fore and aft, and the iuter-antennular septum is 

 formed chiefly by a process of the epistome ; again, the antennal peduncle stands 

 quite clear of the front, not being in contact with or at all overlapped by the 

 frontal margin. 



The whole difference, remarkable though it is, is due to an overgrowth 

 of the epistomial portion of the inter-antennular septum, which pushes up the 

 front, and this overgrowth seems to occur (only) in old individuals of the 

 female sex. 



Length of carapace l-}i inch, breadth 2 A inches, depth Hnds inch. 



£,r 



6946 



6960 



3 

 5511 



10 



No locality recorded. 



Sibsagar, Assam. 



Captain Butler. 



S. E. Peal. 



1 9. 



1 9 , with about a dozen 

 young attached. 



This " variety " may be merely a matter of advanced age. I mention it, 

 however, as it is striking, and as the overlapping of the antennae, or otherwise, 

 by the front has been used as a generic character in this family. 



