15 



V. Trachypeneus, nov. Rostrum' toothed dorsally only. No pleuro- 

 branchise on the last two thoracic somites. Bpipodites absent from the external 

 maxillipeds as well as from the last two pairs of legs. Exopodites present on 

 all, or all but the last pair, of legs. Antennular flagella moderately long. The 

 carapace is longitudinally fissured in the post-orbital region on either side. Type 

 P. anclioralis Sp. Bte. 



VI. Xiphopeneus, S. I. Smith, Proc. U. S. Nat. Mus., VIII. 1885, p. 188. 

 Rostrum toothed dorsally only. No pburobranchia? on the last two thoracic 

 somites. Epipodites absent from the external maxillipeds. as well as from the 

 last two pairs of legs. Exopodites present on all the legs (those of the last 

 pair very small) . Antennular flagella long. The carapace is fissured longitudinally 

 on either side from the orbital nearly to the posterior margin. The last two 

 pairs of thoracic legs are very loug and flagelliform. Typ*; I'. Kroyeri Heller. 



The above arrangement is founded on a study of tbe material in the British Museum. 



The deep-sea species of Peneus collected by the Investigator all belong to 



the subgenera lletapeneus and Parcupeneus, and have the following branchial 

 formula : — 

 , . Arthrobratichice. 



Total. 



1 + 5 ep. 



6( + r) 



5 = 17( + r) + 5ep. 



Syrtojjsis of the Indian Deep-sea species of Peneus. 



Rostrum in both sexes much more than half the length of the rest of the 

 carapace measured in the mid-dorsal line : carapace not longitudinally 

 fissured : — 



1. Tomentose : upper edge of free portion of rostrum with 6 or 7 

 teeth : lobes of copulative organ of the first pair of male 

 abdominal apendages unequal : — 



i. Fourth and fifth abdominal terga distinctly subcarinate 



on either side of the median carina 

 ii. Fourth and fifth abdominal terga obscurely angulated on 

 either side of the median carina 



P. coniger. 



P. coniger var. 

 andamanensit. 



