23G Capt. A. C. MacGilchrist on Decapod Crustacea 



A small carina bcj^ins on the posterior two thirds of the 

 fourth abdominal segment, and is continncd backwards ; on 

 the sixth segment it is a rigid ucil-markcd carina which 

 terminates abruptly at the posterior margin. There is no 

 tooth or spine on any of these segments. The third abdo- 

 minal segment has neither carina nor spine. The sixth 

 abdominal segment is barely twice as long as high. The 

 telson has had its tip broken off. 



Only one specimen (a female) has been obtained — trawled 

 at Sta. 287, Arabian Sea, 150G fathoms — and it gives the 

 following measurements : — 



mm. 



Length of rostrum 10 o 



„ carapace with rostrum til-G 



„ autennal scale 31 



Breadth of „ „ 12-3 



Length ofsixtli abdominal scfiiiieiit I'-l 



,, eiidopodite of tail-fau 23-.") 



,. exopodito ,, 32o 



Length from tip of rostrum to tip of tolton (about) lo7 



This species is most closely connected ^Yith B. inoratus, 

 but can be distinguished from it by the points of difference 

 already noted. From B. 2\inneri and B. bras'ilicnsis it can 

 be distinguished by the presence of an hepatic spine and t!ie 

 absence of teeth on the earinge of the abdominal segments. 

 In B. Bartletli there is a long spine on the dorsum of the 

 fifth abdominal segment. In B. alius the posterior margin 

 of the sixth abdominal segment is elevated to form a trans- 

 verse ridge. 



Will be figured in an early issue of the " Illustrations of 

 the Zoology of 11. 1. M.S. ' Investigator, 



3 }} 



Gexxadas, Spence Bate. 



Gennadas carinatus (?), S. I. Smith. 



Benthesicymus carinatus, Smith, Alb. Crust, in Rep. U.S. Fish. Comm. 

 1882, p. 39G ; Alcock and Anderson, J. A. S. B. pt. ii. vol. Ixiii. 

 1894, p. 147 ; Alcock, Desc. Cat. Lid. Deep-sea Crust. 1901, p. 46. 



At Sta. 306, Arabian Sea, 930 fathoms, a large specimen 

 (apparently the female of this species) was trawled. Previous 

 to this there was only one specimen (a male, caught in the 

 same locality, near the Laecadivcs, 902 fathouis) in the 

 Indian Museum. 



The following are the measurements of this female : — 



