DEPTHS OF THE OCEAN 



1 



lanthina, Carinaria (see Fig. 122, p. 154), Pterotrachea (see Fig. 123, 

 p. 154), and Glaucus, which were taken in abundance in the southern 

 section of our Atlantic cruise. 



Of the large group of Cephalopoda (squids 

 and cuttle-fishes) previous expeditions ob- 

 tained very few in their small tow-nets, those 

 captured being generally taken in the bottom 

 trawls, and it was uncertain whether they 

 lived at the bottom, or in intermediate 

 depths, or near the surface. It has long 

 been recognised, however, that many Cepha- 

 lopoda are true pelagic animals, and in the 

 sixties of last century Japetus Steenstrup 

 applied the term " Decapodes pelagici " to 

 the group CEgopsidae. The Prince of 

 Monaco not only captured Cephalopods in 

 his pelagic trawls, but also obtained them 

 from the stomachs of whales which he shot, 

 his material being reported on by Joubin.^ 

 During the " Valdivia " Expedition the large 

 vertical nets captured a wealth of new forms 

 belonging especially to small types, and 

 Chun in his narrative draws attention to 

 the remarkable Cranchiidae and the little 

 Spirula. Chun has recently published the 

 first part of his report on the " Valdivia " 

 collections of Cephalopoda, dealing with the 

 CEgopsidae." 



It was a special pleasure to me that 

 Chun undertook to describe the Cephalopoda 

 obtained during our Atlantic cruise, and his 

 report, which has just been completed, is 

 available for this preliminary record of the 

 results. His determinations are given in the 

 list on pp. 595-597, and comprise 43 species 

 in all, 3 or 4 of which are new to science, 

 besides some larval forms, the identity of 

 which is uncertain. 



The Cephalopoda are generally divided 

 into two groups according to the number of 

 tentacles, those with ten arms or tentacles 

 being termed Decapoda, and those with 

 eight tentacles Octopoda ; the Decapoda are 

 subdivided into CEgopsidae and Myopsidae. 



the Octopoda have a membrane covering the eye, but in the CEgop- 

 sidae this is perforated. 



^ Joubin, " Cephalopodes provenant des campagnes de la Princesse- Alice," Campagnes 

 scientifiques du Prince de Monaco, Fasc. xvii., 1 900. 



2 Chun, Wiss. Ergeb. " Valdivia" Expedition, Bd. 18, 1910. 



Fig. 434. 



Pterygioteuthis giardi, Fischer (f ). 



( From Chun. ) 



The Myopsidae and all 



