222 ASPIDOBRANCHIA. PATELLADZ. 
Shell with irregular radiating ribs, without yellow, grey or 
green, with variegated rays within, the apex nearly central. 
Length rarely exceeding two inches and a half. Height one 
inch and a half. 
Animal with the sides of the mantle dirty white, yellow or 
testaceous. Foot underneath whitish, dirty or black grey. 
Tentacles blackish or grey. 
Inhabits rocks very commonly on all the shores of Europe. 
The shell is sometimes conic, sometimes more or less de- 
pressed. The elevated radiating lines are always irregular in 
size, and often assume the form of ribs, having smaller ribs or 
elevated lines between them. In young shells the apex is placed 
anterior to the centre. 
The colour of the outside varies but little, but on the inside 
it is very inconstant, being pale green, glaucous, yellow, testa- 
ceous, reddish purple or bluish red, and radiated with dark 
brown or purple brown stripes, which are often interrupted, 
rarely reach the summit, and are sometimes wanting. 
The conic variety is most frequently only striated, whilst the 
depressed one has elevated ribs. These varieties, however, 
pass so insensibly into each other, -as to leave no doubt as to 
their specific identity. 
The spiral tongue is beset with slightly bent rows of short 
spines, each row consisting of six, the four middle ones simple. 
The lateral bifid organs of mastication are composed of five 
cartilaginous pieces, the superior of which seems to perform the 
function of an upper jaw. 
2, PATELLA PARVA. 
P. testé subelongata, depressi, obsoletissimé radiato-costata, 
concentricé striata, apice subantico ; epidermide cornea. 
Patella parva, Da Costa, Brit. Conch. vu. t. viii. f. 11; Donov. 
Brit. Shells, t. xxi. f. 2; Mont. Test. Brit. 480 ; Flem. 
Edinb. Encycl. vii. 
Patella virginea, M. §& R. Trans. Linn. Soc. vii. 235 ; Dill. 
Desc. Cat. 1052; Turt. Conch. Dict. 136. 
Habitat in mari, szepius in profundo, lapidibus et thalassophytis 
adherens. Alt. $ unc. 
