180 THE VOYAGE OF H.M.S. CHALLENGER. 



Histiopsis,^ Hoyle. 



50CZ3/. resembling Calliteuthis, Verrill, in shape and in tlie pigment spots scattered 

 over it. Siphon with a suspensory ligament and a valve. 



Head large and broad ; eyes very large. 



Arms webbed to some extent between the dorsal, dorso-lateral, and lateral pairs. 

 Suckers small in two series. 



Tentacles truncated in the only known specimen. 



Gladius resembing that of Loligo, but short and broad. 



This genus is erected for a unique specimen which was brought up by the trawl in 

 the middle of the South Atlantic ; as will appear in the sequel it presents characters 

 which show it to occupy a position intermediate between Calliteuthis and Histioteuthis. 



Histiopsis atlantica, Hoyle (PL XXX. figs. 9-15). 



1885. Histiojpsis atlantica, Hoyle, in Narr. Chall. Exp., vol. i. p. 273 (nomen tantum). 

 1885. „ „ Hoyle, Diagnoses IL, p. 201. 



1885. „ „ Hoyle, Prelim. Eep. IL, p. 306. 



iZ"a6iia«.— Station 333, Mid-South Atlantic, March 13, 1876; lat. 35° 36' S., 

 long. 21° 12' "W. ; 2025 fathoms ; Globigerina ooze. One specimen, $ . 



Tlie Body is short and conical ; acuminate and curving gently downwards posteriorly. 

 The Jin is about one-third the length of the body and considerably broader than long ; 

 each half is roughly semicircular and narrows into its insertion both in front and 

 behind. The mantle-margin is in general transverse, but projects slightly as a blunt 

 rounded angle in the dorsal median line. The mantle-connective consists of a groove 

 with a narrow median fillet in the mid- dorsal line fitting into a corresponding cartilaginous 

 surface on the back of the neck, and of a long linear ridge extending up to the margin, 

 which fits into a shorter, groove on the base of the siphon; this is broad, short, and 

 conical, has a thick suspensory ligament, through the skin of which two muscles may be 

 distinguished, and a distinct valve. 



Tlie Head is as large as the body, rounded at the sides, and flattened above and 

 below. The eyes appear to have been enormous, one is distended and protrudes from its 

 orbit, whilst the other is shrivelled (fig. 9). There is no auricular crest nor preocular 

 pore, but behind each eye is a white papilla. 



The Arms are about equal in length to the head and body together ; the dorsal are 



1 Contracted from " Histioteuthopsis." There being only one species the generic diagnosis is of conise merely 

 provisional. 



