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MANUAL OF ZOOLOGY 



tion, and surrounds the mouth. A distinct head is pres- 

 ent, and the foot assumes the appearance of a system of 

 appendages of the head. In the cuttle-fishes (Fig. 182), 



jaws inf 



manl 



Fig. 183. — Nautilus pompilius, diagrammatic lateral view of a female specimen 

 enclosed in its shell, cart, cartilage; cten, ctenidia; kd, hood; iuf, funnel; 

 jaws, jaws ; mant, mantle ; >/iant' , dorsal mantle-fold overlapping the coil of the 

 shell; mus, position of lateral mass of muscle; rtid, nidamental glands; sept, 

 first septum; siph, siphuncle. (After Keferstein.) 



squids (Fig. 187), Octopi, and Argonauts (constituting the 

 sub-class Dibranchiata) the main part of the foot is composed 



