MOLLUSCA. SOLENOSTOMATA. 329 



II. Shell turrited ; whorls subcorneal, slightly embracing. 



1. "BvcciinDJe.. Shell truncated or rounded anteally; the canal 



scarcely produced beyond the anterior margin of the lip, and 

 bent towards the left. 



2. MuRiciDiE. Shell acuminated at the base ; the canal produced 



beyond the anterior margin of the Hp, and either straight or 

 bent. 



3. CcRiTHiADiE. Aperture of the shell oblique; canal short, trun- 



cated or recurved. 



4. Strombusid^. Outer-lip spreading with age, and having a 



notch or sinus near the commencement of the canal for the 

 • < passage of the head. 



