igog.J A. Ai^coCK : New Freshwater Crabs. 245 



numerous and a little smaller. Nine males and three females 

 from the Kakhyen Hills and Yunnan ; in Dr. Anderson's Yunnan 

 col.ection. 



10. Potamon (Potamon) pealianum, Wood-Mason, 

 var. antennarium. 



In this " variety " — using the term without any definite 

 implication — the antennular fossae are wide fore and aft owing 

 to an overgrowth of the epistomial portion of the inter-antennu- 

 lar septum. In consequence of this pushing up of the edge of the 

 front the antennal peduncles stand quite clear of the front, being 

 neither in contact with nor overlapped by the front. I find this 

 abnormality in four old females only, two of them fromSibsagar, 

 Assam, two from an unrecorded locality. 



II. Potamon {Potamon) turgidulum , sp. nov. 



Belongs to the pealianum and tumidum clan. Resembles 

 P. tumidum, Wood-Mason, in form and size, but differs as follows : — 

 {a) The grooves of the carapace are more superficial ; {b) the front — 

 in individuals of equal size — is narrower, and its edge is distinctly 

 bilobed ; (c) the edge of the post-orbital crests is thin and well de- 

 fined, not thick and somewhat confused with the rugosities of the 

 carapace as it is in tumidum ; [d) the merus of the external max- 

 illipeds is as long as broad ; {e) the legs are longer — in individuals 

 of equal growth — the second (longest) pair being considerably longer 

 than the chelipeds. Eleven males and six females (one with eggs) 

 from Burma. The length of the carapace in adults is less than an 

 inch. 



T2. Potamon {Potamon) tumidulum, sp. nov. 



Very close to tumidum and turgidulum, but the carapace is less 

 convex, and the post-orbital crests are very rugose and blunt- 

 edged. Though not so convex dorsally the carapace is hardly less 

 deep, its depth being half its length. The front is less than a 

 third the greatest breadth of the carapace in adults — in turgidulum 

 it is a third, in tumidum more than a third. The chelipeds are 

 more unequal, and they and the legs are somewhat hirsute. 

 Eight males, eight females, and eight young from Pharping. Nepal. 

 In the largest specimen (a mature female) the carapace is only fths 

 of an inch long. This species could not be placed in the Geotelphusa 

 group as its post-orbital crests, though blunt-edged, are tumid and 

 bold. 



13. Potamon {Potamon) simtdum, sp. nov. 



Very close to P. austenianum, Wood-Mason, and having the 

 same remarkably long, slender legs, but differing in the following 

 particulars :—{a) The carapace is shorter and wider, and its areo- 

 lation is much less distinct ; {b) the front is much narrower— not 



