A SYNOPSIS 



THE LINNEAN GENERA. 



1. CHITON.— Plate 1. 



Animal, a Lophyrvis. 



Shell, multivalve (valves or plates), generally eight, arranged longitu- 

 dinally ; moveable on each other, like the joints in the tail of a 

 lobster ; connected by a projecting coriaceous border, which is 

 either plain, spinous, or scaly. 



2. LEP AS— Plate 1. 

 Animal, a Triton. 



Shell, multivalve, either conical or compressed, formed of several 

 valves : the conical shells are sessile, strongly fixed at the base, 

 and the valves are articulated or joined to each other by delicate 

 sutures. The compressed shells are not articulated, but con- 

 nected by a membrane, and supported on a flexible retractile 

 pedicle. 



3. PHOLAS.— Plate 2. 



Animal, an Ascidia. 



Shell, multivalve, consisting of two principal valves, with several 

 smaller accessory valves on the hinge. Hinge recurved, united 

 by a cartilage, and having a strong incurved tooth in one valve. 

 Shell always gaping at one end, generally at both. 



