374 A. E. Verrill Decapod Crustacea of Bermuda. 



longed and is rounded distnlly. Hence I am disposed to consider 

 the group including P. >''//// a distinct genus. 



In these characters this species agrees with P. /l<<</icus, the type 

 of the genus. I have compared it witli a number of characteristic 

 specimens of the latter from .Japan. (Vale Mus., coll. K. S. Mor>e.) 



Charybdella M. J. Rathbun. 1897 = r/-i./m.x Stimpsnn. 1S(}U (name preoccupied). 



This genus was established for ('. rn1>r<i. as the only species. Tin- 

 latter, which is a common West Indian and Florida specie-, differ- 

 from our species of Aclnlnii* in several important cliaracters. It- 

 outer maxillipeds have the inenis short ; the maims of the cheliped- 

 bears three distal spine- ; the antero-marginal teeth are alternately 

 larger and smaller ; the antenna! sinus of the orbit is much con- 

 tracted ; the inner orbital tooth is deeply bilobed. But the <'h- 

 rybd'llc t>iinidula, referred later to the -ame genus by Mi-'- IJathbun. 

 would seem to go about as well in Ac.htlniis, when- it had previously 

 been placed, for its characters are partly intermediate between tin- 

 two genera. In most re-pects it is very closely related to A. <1 il>hr*ii, 

 which it closely resembles in the strong areolation of the carapace ; 

 the frontal denticles; and bilobed interorbitala ; the distal denticula- 

 tion of the merus of the swimming feet, etc. \\\\\, owing mainly to 

 the alternation of large and small marginal teeth, I have left it in 

 Charybdella. The characters of the antennal sinus and antenme 

 are intermediate. 



Some speciti! tli<i<tnostic characters of the Bermuda spec/is t,\d some others 

 'Kin-/!/ allied) of Portunus, Acheloiis, and Cliin-i'l>,l,-lla. 



1. Carapace convex, nearly smooth, glossy, with feeble areolations and few 



hairs _______ __________ ............ _. ................ .. ________ Sayi 



2. Lateral marginal teeth alternately distinctly larger and smaller. 



tuiniihiln : rubra 



3. Posterior corners of carapace distinctly angular ......... ______ spinicur/ins 



4. Posterior lateral marginal spine scarcely longer than the Te&t-.dr/>n-ssifrons 



5. Inner orbital tooth bilobed, so that the front has eight teeth or lobes 



between the orbits, counting the inner orbitals. 



tumidula ; rubra; Smithii ; Gibbesii (bilobing feeble) ; spinimnnns 



6. Carapace when fresh having a pair of well denned, round, ocellated, rod 



spots on the flanks . . ..................... ..... ______ ............ Sebre 



1. Carapace having a pair of ill denned red or brownish spots on the flanks. 



tumidula 



8. One or two round silvery spots on each side of carapace, near bases of 



marginal spines .. ............................ . .............. Gibbesii 



9. Herns of chelipeds having five or six spines on the inner margin. 



Gibbesii ; rubra (not always); Seba; ; depressifrons ; spinnnnnus (sometimes). 



