UNIVALVES—PATELLA. 185 
able inthe P. equestris, P.sinensis, and P. duplicata ; 
these are commonly designated Cup-and-saucer Lim- 
pets. 
The last division has a very peculiar character, the 
interior being furnished with a transverse partition, 
giving the shell the appearance of a slipper; the P. ne- 
ritoidea, P. porcellana, and P. fornicata resemble Nerites. 
The rarest shells of this genus are the P. persona- 
ta, P. trochiformis, P. mytiliformis, and P. macro- 
schisma. 
The Limpets are usually found adhering by their base 
to rocks, stones, fuci, and other marine substances, from 
which they are not easily detached. They inhabit 
the Indian, Southern, European, Northern, and Medi- 
terranean seas, the American and Indian Islands, 
the Atlantic, and the shores of China, Greenland, and 
Iceland. 
The Patellee derive their name from their resemblance 
to alittle dish or bason (Patella). 
Dryiston 1.—Shell with the summit obtuse, and the margin entire. 
Scientific Name. Locality. Common Name. 
Pellucida ------- Britain, Norway, Medi- 
terranean -+++--- Pellucid Limpet - 
England, Northern Ocean Smooth --- do -- 
Leevis «+++ +-+-:- 
Radians --:----: New Zealand, ‘Terra del 
Fuego --++++sereeeee: Grey-mottled do 
Rota -----:++++. E,& W. Indies -------- Roundish -- do - 
Testudinaria ---- Norway, East Indies ---- "Tortoise-shell do - 
Clealandi:--++-- Bangor, Ireland -------- Clealand’s « do -- 
Small tortoise-shel} 
Testudinalis --- Norway, St. Domingo -- 
