MOLLUSCA— CEPHALOPODA. 



145 



of the skin forms a mantle-fold on the under surface and Gallery- 

 encloses the gills. In front of the gills another part of the 

 foot is folded together to form a funnel through which the 

 water that has passed into the gill- chamber can be forcibly 

 squirted out. By this means the animal can be driven 

 backwards through the water (Fig. 87). The mouth is armed 

 with strong horny jaws, shaped like a parrot's beak (Fig. 

 78 a-c). The power of locomotion the concentration of the 



Fig. 78. — Cephalopoda, a, b, c, Rhyncholiths, fossil beaks of a nautilus 

 from the Miocene of Malta ; nat. size ; d, the Pearly Nautilus in its 

 shell, part of which has been cut away so as to show the chambers 

 and the siphuncle running through them. On the animal are seen 

 the visceral hump (a), the muscle and ring of attachment (g), the 

 eye (s), the funnel (k), the tentacles (j>), and the hood (n). e and /, 

 the squid, Loligo ; the shell (e) is seen from the back, the animal (/) 

 from the under side ; d, e, f, are much less than natural size. 



chief organs in the forepart of the body, and the strong jaws, 

 show that these animals can prey upon others, even on those 

 with hard coverings, and lead one to regard them as more 

 highly developed than the other MoUusca. All these features Between 

 can be recognised in the exhibited specimens and models of ^all^eases 

 living cephalopods. Further study of these specimens will Table-ease 

 show certain differences between the forms that have been l. 

 mentioned. Thus the cuttle-fish, squid, and octopus have 

 rather long distinct arms, and these are furnished with 

 suckers strengthened by horny rims ; in the nautilus 



L 



