[471 



DECAPODA FROM ALBATROSS DREDGINGS. 

 PENiEID-aJ. 



391 



Benthcecetes Bartletti, gen. uov. 



Benihefsicymus Bartletti Smith, Bull. Mus. Comp. Zool., x, p. 82, pi. 14, tigs. 



1-7, 1882. 



(Plate X, Fig. 8.) 



Specimens examined. 



The second gnatLopods, which were wanting in the single imjierfect 

 specimen described from the " Bhike" collection, show that this species 

 does not belong to Bate's genus Benthesicymus, to which it was very 

 doubtfully referred. In Benthesicymtis the second gnathopod is de- 

 scribed as terminating in a " sharp-pointed dactylus," which is after- 

 ward referred to (under Gennadas) as " cylindrical and sharp," while in 

 our species the dactylus of the second gnathopod is short and flattened, 

 and truncated at the tip — differences undoubtedly accompanied by other 

 differences in the oral appendages, which are not described in Bate's 

 species. The genus here proposed is further characterized by the struct- 

 ure of the maxillipeds and first gnathopods, and apparently also by the 

 form of the dactyli of the fourth and fifth perteopods. The number and 

 arrangement of the branchi*, as shown in the following table, is appar- 

 ently the same as in Bate's genus. All the podobranchiae, except the 

 posterior one on each side are, however, much more slender than the 

 corresponding arthro- and podobranchise, and the highest and most an- 

 terior of the two branchife at the base of the second gnathopod arises in 

 the border of the articular membrane, corresponds very nearly in size 

 and position with the podobranchiae of the somites back of it, and might, 

 perhaps, more properly be considered a pleurobranchia than an arthro- 

 branchia, as it is in the following table. There is the same difficulty in 

 distinguishing between pleuro- and arthrobranchite in many other 

 genera. 



The specimens from the Albatross collection enable me to correct 

 somewhat the original de8cri])tion of the species, and I therefore re- 

 state the more essential characteristics. 



