2 THE OCTOPUS. 



Of the ten-footed section of the cephalopods, there are four 

 "families"; two only of which exist in Britain — the Teuthid?e, and 

 the Sepiidie. The Teuthidae are the Squids, or Calamaries, 

 represented by the long-bodied Loligo vulgaris, that has along its 

 back a gristly, translucent stiffener, shaped like a quill pen; from 

 which and its ink it derives its names of " calamary," " pen-and-ink 

 fish," and "sea-clerk." The Sepiidae are the Cuttles; as a type 

 of which we may take the common '' cuttle-fish," Sepia qfficinalisy 

 the owner of the hard, calcareous shell often thrown up on the 

 shore, and known as " cuttle-bone," or '* sea-biscuit." 



Of the eight-footed cephalopods, — the Octopoda, — there are 

 two families ; namely, the Octopidae, and the Argonautidse. 

 The first only is found on our coasts. The British members 

 of it are the common Octopus, O. vulgaris, and the Eledone, 

 E. cirrosa, a genus chiefly distinguished from the octopus by 

 its having only one row of suckers, instead of two, along its arms 

 or feet. The Argonautidse, which inhabit warmer seas than ours, 

 and approach no nearer to us than the Mediterranean and Adriatic, 

 are represented by Argo7iauta argo, the "Paper Nautilus," — so 

 called from the peculiar texture of its shell, and the similarity of its 

 shape to that of the true Nautilus, N. pompilius, from which, how- 

 ever, it differs greatly in organisation. 



All of these four " families " have two plume-like gills, — one on 

 each side — and are therefore placed by Professor Owen in the 

 *' order," Dibranchiata. To this order belong also the extinct 

 Belemnites, and the still living Spirula, only one entire specimen 

 of which has ever been obtained, and that was in New Zealand, 

 though its beautiful internal shells are sometimes thrown up on 

 the shores of Devon and Cornwall. 



The Tetrabranchiata, or four-gilled cephalopods, are represented 

 by a single living genus — the Pearly Nautilus, N. po7?ipilius, — but 

 in Silurian times by 34 genera, and more than 1400 species.'^ 



* See an interesting article on the fossil and recent cephalopoda, by Henry 

 Woodward, F.R.S., in the Student, Nos. xix. and xxii. 



