464 



THE OCEAN WORLD. 



calls Dibranchiata, characterised by the presence of two branchiae, 

 which would bring together all the naked Cephalopods, including 

 Sepia, Loligo, Octopus, Kassia, and Ommastrephos ; and Tetrdbran- 

 chiata, having four branchiae, to which the Nautilus, and most of the 



fossil Cephalopods, such as 

 the Ammonites, belong. Most 

 of the first group are repre- 

 sented in the British seas, but 

 the second are altogether 

 absent. 



The Decapoda are of all 

 sizes. Dr. Grant describes 

 the body, or mantle, of Sepi- 

 ola vulgaris, found on our 

 coast, as measuring about six 

 lines in length, and as much 

 in breadth, while the head 

 Fig. 322. octopus macropus (Risso). measures four lines in length, 



and, from the magnitude of the eyes, must be equal in breadth with 

 the body. In Onyclioteuihis, distinguished for its uncinated suckers, 

 they are found of the size of a man. In Cook's first voyages, the 

 naturalists to the expedition, " Banks and Solander," to quote Professor 



Fig. 323. Octopns brevisses 

 (D'Orbigny). 



Fig. 324. Octopus horrldus (D'Orbigiiy). 



Owen's account, "found the dead carcase of a gigantic species of 

 this kind floating in the sea between Cape Horn and the Polynesian 

 Islands, in 30 44' S. lat., and 110 10' W. long. It was surrounded 

 by sea birds, which were feeding on its remains. From the parts of 



