G 



(lilt dt> tO I Ik M oil II SCI l . 



Amphineura (Chitons or ' coat-of-mail ' shells) and Scaphopoda 

 (Tusk-shells). 



Certain animals belonging to oilier divisions of the Animal 

 Kingdom have shells that resemble more or less closely those of 



Fig. I. 



General anatomy of Trochus ( X 3) showing the position of some of the more 

 important organs. 



a. eye ; b. gill ; c. eut edge of mantle ; d. crop ; e. oesophagus ; /. stomach : 

 g. intestine; h. rectum; i. pericardium; j. radula sac; k'k". kidneys; I. liver; 

 m. genital gland. 



Mollusca, and were, therefore, associated with the latter by the 

 older naturalists. Such are the Lamp-shells (Brachiopoda), which 

 superficially resemble Lamellibranchs but differ widely in their 

 internal structure, and the Barnacles (Cirripedia), which are 

 greatly modified Crustacea. 



