OF THE ODOXTOPHORE IN CERTAIN MOLLUSCA. 491 



Fig. 29. Longitudinal ventral muscles, vis, cut, radula and adherent infraradular sheet 

 laid back, showing cartilages, c ; f/J/-, downward prolongation from circular 

 protractor of lips. 



Fig. 30. Ventral transverse fibres of cartilages (vtf) cut open, showing dim', the deepest 

 set of longitudinal dorsal muscles; c', backward prolongation of the 

 cartilages. 



Fi». 31. Cartilages completely cut apart, showing dorsal and ventral transverse fibres. 



Fig. 32. Left side of apparatus m situ ; letters as in figs. 26-28. 



Fig. 33. Superficial muscles of left side cut away, showing left of framework ; irs, line 

 of attachment of radula and infraradular sheet to side of mouth, deeper 

 ventrally ; apex therefore rocks forward and upward at irs. 



Fig. 34. Left cartilage completely removed, and median section completed. 



Fig. 35. Lateral vertical section of anterior portion of Molluscan odontophore, 

 diagrammatic. 



Explanation of the Colours. 



Cartilages Blue. 



Infi-a-radular sheet, with its dorsal and ventral muscles . . Red. 



Eadula Yellow. 



