BENTHESICYMUS ALTUS. 203 



in the two sexes. The dorsal portion of the cervical groove is more distinct 

 than in H. spinidorsalis. The sixth abdominal segment is longer than in 

 H. spinidorsalis, and there is a difference affecting the inner branch of the 

 second abdominal appendages of the male, viz. the tooth-like process, which 

 is in H. spinidorsalis shorter than the external plate, in H. triton is developed 

 into a broad plate which exceeds in length the external j^late. This differ- 

 ence will be most easily comprehended by inspection of Figs. 1' and 2 on 

 Plate L. 



The podobranchia of the twelfth somite is even smaller than in H. 

 sjnnidorsalis. 



Length, 127 mm. ; carapace, 44.5 mm. ; rostrum, 6 ram. 



Station 3360. 1672 flithoms. 1 fern. 



3374. 1823 " 1 male, 5 fem. 



" 3381. 1772 ■' 3 males, 1 fem. 



This species is perhaps identical with Hemipeneus carpenteri Wood-Mason,* 

 dredged in the Laccadive Sea and in the Bay of Bengal, 1091-1644 

 fathoms. 



BENTHESICYMUS Batk. 



Ann. Mag. Nat. Hist., 5tli Ser., VIII. 190, 1881 ; Rep. Challenger Macrura, p. 326, 1888. 



Benthesicymus altus Bate, 



Aun. Mag. Nat. Hist., 5th Ser., VIII. 191, 1881 ; Rep. ChaUenger Macrura, p. 336, Plate LVIII. 



Kg. 1, 1888. 



1 male, 3 fem. 



1 fem. 



1 male, 1 fem. 



1 male, 2 fem. 



2 males, 5 fem. 

 1 male, 1 fem. 

 1 fem. 



1 male, 1 fem. 



2 males, 1 fem. 

 2 males, 9 fem. 



In Bate's figure of this species there appears to be a small spine on the 

 side of the carapace, although none is mentioned in his description. In the 

 "Albatross" specimens there is no spine at this place. The fragile filiform 



* Ann. Mag. Nat. Hist., 6th Ser., VII. 189, VIII. 286, 1891. 



