REPORT ON THE CRUSTACEA MACRURA. 339 



Benthesicymus mollis, n. sp. (PI. LVIII. fig. 2). 



This species very closely resembles Benthesicymus brasiliensis. so much so that I 

 considered it to be that species, until I examined the structure of the branchial plumes 

 and found them to have the ultimate lobes both broader and shorter. The telson 

 (fig. 2z) which is partially damaged in the specimen taken as the type, is deeply grooved 

 dorsally to the anterior extremity. 



The texture of the external surface is extremely thin and soft, as in most specimens 

 of this genus. 



Length, 76 mm. (3 in.). 



Habitat— Station 133, October 11, 1873; lat. 35° 41' S., long. 20°. 55' W.; near 

 Tristan da Cunha ; depth, 1900 fathoms; bottom, Globigerina ooze; bottom tempera- 

 ture, 35°-4. Trawled. 



Gennadas, Spence Bate. 

 Gennadas, Sp. B., Ann. and Mag. Nat Hist., ser. 5, vol. viii. p. 191, 1881. 



Resembles Benthesicymus, but differs in having the dactylos of the second pair of 

 gnathopoda spatuliform, instead of cybudrical and sharp. The rostrum is short, laterally 

 compressed and dorsally crested. The ophthalmopod is flattened and carries a large 

 tubercle or complementary eye on the inner margin. The first pair of antennae is about 

 half the length of the carapace and has the second and third joints broad. The first 

 joint is deeply excavated to receive the eye, and the terminal joint articulates with the 

 second at the inferior angle only, and carries two long flagella of unequal diameter. 

 The second pair of antennas is long and slender, and carries a large scaphocerite that 

 gradually narrows towards the distal extremity. 



The mandibles carry a two-jointed synaphipod of which the first joint is broad and 

 ovate, and the second narrow. 



The first pair of gnathopoda is short and has the meros broad and scpaamiform. 



The second pair is seven -jointed, long and narrow, and terminates in a spatuliform 

 dactylos. 



The first pair of pereiopoda is chelate, short and robust. The second is chelate, 

 long and stout. The third is still longer and rather slender, and the two posterior are 

 long, slender and feeble. 



Both pairs of gnathopoda carry a mastigobranchial plate and a podobranchial plume, 

 two arthrobranchise, and a small pleurobranchia. The mastigobranchise are rudimentary 

 in their proportions, but become slightly larger on the penultimate pair of pereiopoda, 

 where there is no podobranchial plume, and are altogether absent from the ultimate 

 pair of pereiopoda, as also are the arthrobranchise, the pleurobranchial plume alone being 

 retained. 



