242 



BUBKINGDOM MOLLUSCA. 



Moll' 



usca vera ■ 



HEAD AND FOOT 



PBESENT ; 



Bl- LATERALLY STMMB- 



TRICAL ; FEBT AROUN 



THE HEAD. 



■■I 



Classes. 

 Cephalopoda. 



Laterally onstmme- I 

 trical; foot beneath f Gasteropoda, 



THE BODY ' 



HEAD ABSENT; FOOT PRESENT; 



Mil . J J HEAD AND FEET 



olluscoidea. -j absent; 



liamellibranchlatat 

 - Brachiopoda. 



Shell, dorsal, and 

 ventral valvb. 



Leathery, elastic cot- 1 



BRING ; SIMPLE OR V Tunlcata. 

 COMPOUND. ) 



Compound; moss like. Polyzoa, 



CLASS I. CEPHALOPODA. 



General Characteristics. — The Cephalopods (head- 

 footed) have muscular tentacles or arms around the mouth ; 

 heaked, horny jaws; two large eyes." arms covered with 

 sucking discs ; and a bag of ink, with which most species 

 blacken the water to hide from pursuit. 



CEPHALOPODA. | 



Orders. 

 Two-GILLED. DibraDchiata, Argonaut, etc. 



FouB-GiLLED. Tetrabrancbiata, NaiUilut, etc 



ORDER DIBRANCHIATA. 



General Characteristics. — The Dibranchiates (two- 

 gilled), have an ink-gland and the power of changing color 

 like a chameleon. 



Mg. uis. 



Argonauta argo. Paper Sailor. \. 



The Argonautidae (sailors) are named from the fabulous 



