224 ASPIDOBRANCHIA. PATELLADZ. 
1. PATINA LEVIS. 
P. testa crassiuscula, opacd, seepius complanata, leevis obsolete 
radiato-subcostata, apice subantico. 
Patella levis, Penn. Brit. Zool. 144. t.1. f. 151. fig. inf. ; 
Dill. Desc. Cat. 1043; Turt. Conch. Dict. 137. 
Patella czerulea, Pult. Cat. Dorset. t. xxii. f.6; Flem. Edinb. 
Encycel. 76; Lamarck, Hist. Nat. des Anim. sans Vert. vi. 
328. 
Habitat in mari Britannico vulgatissimé ad radices thalasso- 
phytorum adherens. Alt. 13; lat. t une. 
Shell thickish, opaque, generally depressed, smooth, with ra- 
diating ribs; its apex rather anterior. Length rather more 
than one inch. Breadth seven-eighths. 
Inhabits the British seas at the roots of marine plants. 
Its apex is rarely elevated. Young shells are generally pel- 
lucid, and are rayed with blue or chestnut: the rays are often 
interrupted: in this state, the apex is placed close to the ante- 
rior margin. 
2. PATINA PELLUCIDA. 
P. testa pellucida, leevi, elevata, ceeruleo- aut castaneo-radiata ; 
apice anticé deflexa, concentricé striolata et obsoletissimé 
radiato-costata. 
Patella pellucida, Linn. Syst. Nat. xx. 1260; Gmel. Syst. Nat. 
3717; Donov. Brit. Shells, t. m. f. 1; Mont. Test. Brit. 
477; M. § R. Trans. Linn. Soc. vii. 233; Flem. Edinb. 
Encycl. vii. 76 ; Dill. Dese. Cat. 137; Turt. Conch. Dict. 
137. : 
(3. testa apice maculis duabus czeruleis notata. 
Patella bimaculata, Mont. Test. Brit. 182. t. xii. f. 8; M. & 
R. Trans. Linn. Soe. vii. 235. 
Habitat in mari Britannico vulgaris, thalassophytorum foliis 
adherens. Alt. 1 unc. 
Shell pellucid, smooth, elevated, radiated with blue or chest- 
nut ; its apex anterior and deflexed ; its surface concentrically 
striolated, and very obsoletely ribbed. Length rarely exceed- 
ing an inch. 
