CIIAI'TEIJ U.— continued. 



ANALYTICAL INDEX. 



103 



2. Chiton vulgaris, 



Length and figure of shell, &c., 



Food, ..... 



Motion slow, 



Spawn, ..... 



Survives long, 



Note — species peculiar to Scotland, 



2. Patella — The Limpet, 

 A comprehensive group, not properly defined, 



Ancylus fluviatilis, 



Resembles the limpet, but inhabits fresh waters. 



The shell and animal described. 



Has considerable activity. 



Food, .... 



Reproduction — observations on specimens, 



3. Ancylus lacustris, 

 This species confounded with the preceding, 

 Shell and animal described. 

 Food, ..... 

 Spawn, .... 

 Breed from beginning of June to August, 

 Plate VI. described, . 



Patella vdlgata, 



The common limpet abundant. 



Animal described. 



Form and colour of shell. 



Habits and use. 



Patella pellucida. 

 Shell and animal described. 

 Occurs on the common Laminaria, 



Patella undata — The Waved Limpet, 

 Form of the shell, &c.. 



Patella tesselata, 



Oval and tesselated, 



Colour dingy white. 



Difficult to discriminate species, 



Patella ? . 



Placed here provisionally. 



VOL. III. 



