42 



contiguous edge of the dactylus. The fingers are not in close apposition when 

 closed. 



The legs are hardly longer than the chelipeds ; the length of the propodite 

 of the 2nd and 3rd pairs is about twice its breadth ; the dactyli are longer than 

 the propodites. 



Length of carapace of apparent adults Ifths inch, breadth Ir.r inch, depth 

 xVths inch. 



69.35 



3 ■ 

 6937 



3 ■ 

 69.54 



3 ■ 

 6957 



3 ■ 

 6927 



3 ■ 



21. PoTAMON (Potamon) turgidulum, Alcock. (Fig. 5.) 



A small species resembling P. tuviidum, but conspicuously differing from 

 that species by— (1) the indistinct and very superficial carapacial grooves ; (2) 

 the more elongate merus of the external maxillipeds ; and (3) the longer and 

 slenderer legs. 



It is also very close to P. inornatum Eathbun, but cannot be said to have 

 the sub-branchial regions visible in a dorsal view. 



Length of carapace a little more than four-fifths its greatest breadth, depth 

 usually a little more than half its length. 



Carapace strongly convex fore and aft, areolated as in tumidum, but the 

 grooves are so superficial and so faint that they can only be made out by care- 

 ful illumination. Even the cervictil groove is very faint anteriorly, except at 

 the usual point— in line with the inner angle of the external orbital tooth- 

 where it cuts the post-orbital crests. 



The surface sculpture of the carapace is as described in P. tumidum, except 

 that the pterygostomian regions are less granulous. 



Front not less than one-third greatest breadth of carapace, strongly 

 deflexed, its edge faintly creuulate and distinctly bilobed. External orbital 

 tooth distinct, separated from lower border of orbit by a very shallow 

 notch. 



Lateral epibranchial tooth and notch between it and outer orbital tooth 

 conspicuous. Antero-lateral borders longer than postero-lateral, curved, 

 crenulate, raised. Postero-lateral borders obliquely rugulose. 



Epigastric crests separated from post-orbital crests by tin indistinct groove 



