184 



rNTRODUCTION TO ZOOLOGY. 



III.— CEPHALOPODA— CUTTLE-FISHES. 

 -X 



Fig. 171. — Calamary. 



If we look at a Cuttle-fish {Fig. 171), we notice that tlie 

 head is surrounded by a number of appendages; and tills 

 peculiarity is implied in the term " Cephalopoda.''''* It is 

 •restricted to the third division of the encephalous ]\Iollusca; 

 to that class which is the most elevated in organization. Its 

 superiority is manifested in the muscular, the respiratory, and 

 the nervous systems, and also in the existence of a true in- 

 ternal skeleton of a pecuHar structure, the first approach towards 

 the most obvious characteristic of the vertebrate animals. 



Though the shell of the Pearly Nautilus (Nautilus Pompi- 

 litts, Fig. 172) is common in i.iusoums, the capture of the 



i 

 s i 



-/ 



Fig. 172. — Peablt Nactilcs, •with tue shem, iaid open. 



Fiff. 172— <, Teiitacula.— /, Funnel — g, Foot.— m, Part of mantle.- 

 I, Siphon. 



* From two Greek words, sigiiifj'Lng head-feet. 



e, Kyc- 



