A SYNOPSIS 



OF 



THE LINNEAN GENERA, 



I. CHITON.— Plate 1. 

 Animal , a Lophyrus. 



Shell, raultivalve (valves or plates), generally eight, arranged longi- 

 tudinally ; 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. LEPAS.— Plate 1. 

 Animal, a Triton. 



Shell, raultivalve, 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 de- 

 licate sutures. The compressed shells are not articulated, but 

 connected by a membrane, and supported on a flexible retrac- 

 tile pedicle. 



3. PHOLAS.— Plate 2. 

 Animal, an Ascidia. 



Shell, raultivalve, 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. 



