

THE MOLLUSCA 97 



sands of these baby Octopods perish, being greedily devoured by 

 many fishes, and this high rate of infantile mortality is probably 

 the reason of the great fecundity of the Octopus, Nature by this 

 means maintaining an even balance. 



The Cuttlefish the Kraken of the old travellers and natural- 

 ists differs from its cousin the Octopus both in appearance and 

 mode of life. While the Octopus leads a somewhat hermit-like 

 existence at the bottom of the sea, the Cuttlefish loves a roving 

 life in the surface waters, often appearing in shoals near the coast 

 and far out at sea. Cuttlefish vary greatly in size, some species 

 never exceeding -a couple of inches in length, others attaining the 

 gigantic proportions of upwards of 60 feet. The body may be long, 

 tapering, and cylindrical, or more or less oval. The eight arms 

 round the mouth of the Cuttlefish are much shorter than those 

 of the Octopus, but from within the circle rise two very long 

 additional arms, sometimes thrice the length of the animal, which 

 terminate in a club-shaped expansion covered with suckers. The 

 Cuttlefish employs these for grasping its prey when beyond the 

 reach of the eight shorter arms, and as anchors to moor itself 

 to drifting seaweeds. The two long arms are destitute of suckers 

 except at their terminal expansions, which are covered with them ; 

 and the suckers are even more formidable than those of the Octopus, 

 as they are bordered by a horny ring, having a finely serrated edge, 

 and are mounted on short stalks. In some species the serrated 

 edge is developed into a series of sharp-pointed, incurved teeth, 

 which must sink into the flesh of any unfortunate fish that may 

 be captured, and render its escape absolutely impossible. The 

 Cuttlefish has jaws similar to those of the Octopus, though not 

 quite so large in proportion ; it has an ink-bag, very beautiful 

 internal plume-like gills or branchiae, and embedded in the mantle 

 on the upper surface of the body is the large oblong oval, limy 

 internal shell, familiarly known under the name of " cuttle-bone." 



The Pearly Nautilus (Nautilus pompilus) is an inhabitant of the 

 Indo-Pacific Ocean, and is the only living representative of the four- 

 gilled Cephalopods or Tetrabranchiata. Its large and beautiful 

 shell is a familiar object in museums, and has an outer porcelain-like 

 layer beneath which is the beautiful and harder nacreous or mother- 

 of-pearl layer. The animal differs from all the other living Cepha- 

 lopods not only in the possession of four gills, but also in having 

 H 



