236 THE VOYAGE OF H.M.S. CHALLENGEE. 



length of sixty or seventy feet,^ in all parts of the world, and which have, no doubt, con- 

 tributed to the stories of the sea-serpent. The largest Cephalopod obtained by the 

 Challenger was the type of Cirroteuthis magna; it measures more than a metre in 

 length, and is interesting as being the largest individual of the genus which has yet been 

 obtained. 



The greatest accessions of new species have been to the already large genera Octopus, 

 Sejna, and Loligo, but these are of less interest than the unique specimens which have 

 been made types of new genera, each o£ which presents some character either entirely 

 novel, or important as furnishing connecting links between previously known forms. The 

 genus Amphitretus, for example, has two openings into the branchial cavity in place of 

 one, a disposition found in no other Cephalopod ; while Histiopsis is related closely to 

 Histioteuthis, Chiroteuthis, and Calliteuthis. 



The next section treats of Geographical Distribution, and an attempt has been made 

 to supplement the work of the Challenger by a summary of all that has been recorded on 

 this head. The species have been divided into " littoral " and " oceanic," the latter group 

 including both "pelagic" and "abyssal." Lists of each of these are given, but owing 

 probably to the want of complete information, the same species sometimes appears under 

 two categories ; thus an Ommastrephes, typically pelagic, may be obtained near the coast 

 among littoral forms. It is much to be wished that future collectors will carefully note 

 the exact localities where and the conditions under which specimens are obtained, and 

 thus help to unravel some of the problems which wait solution regarding the distriljution 

 of these animals. 



In the concluding section, which treats of Bathymetrical Distribution, still greater 

 difficulties have been encountered, because in the case of such active creatures it is 

 obviously impossible to assume that they were captured by the dredge or trawl at the 

 greatest depth reached. In the case of the single sj)ecimen of Promachoteuthis, for 

 example, there seems no means of arriving at any conclusion as to the depth whence it 

 was obtained. 



Nevertheless, taking all collateral facts into consideration, evidence is adduced which 

 seems to indicate that Cirroteuthis almost certainly, Bathyteuthis and Mastigoteuihis 

 probably, and possibly even one or two species of Octopus, may be veritably abj^ssal 

 Cephalopods, but apart from the single fact that Bathyteuthis and Mastigoteuthis both 

 have slender filiform tentacles with minute suckers, no structural features have been 

 discovered which will serve to diagnose a deep-sea form from a shallow-water one. 



1 Verrill, Ceph. N.E. Anier., part i. 



