262 PATELLIDA. 
when compared with the commoner appearance of its con- 
gener. The two species inhabit generally different levels, the 
P. vulgata occupying the higher one. This species is partially 
distributed ; it is found tolerably plentiful in an area of half 
a dozen acres near Exmouth, very few of the P. vulgata being 
in company in its own level; but these are congregated im 
great numbers in the higher levels, with the P. athletica rarely 
amongst them. The great distinguishing character of the 
two is the fringe of the mantle, which in the athletica is snow- 
white, but im its congener a pale uniform drab ; it also varies 
in length and thickness; a comparison of them in sea-water 
will at once impress a conviction that they are specifically 
distinct. 
ACM AA, Eschscholtz. 
A. virnetnEaA, Miller. 
A. virginea, Brit. Moll. ii. p. 437, pl. 61. f. 1, 2. 
Patella virginea, Auctorum. 
Animal oblong-oval, pale yellow, mhabiting a subconical 
patelloid shell marked with shallow radiating lines, and minute, 
pink, narrow longitudinal fasciz; vertex anterior; mantle 
even with the shell, bordered with a rather long fimbriated 
fringe, inflected gently mwards; it is interspersed with red 
patches and pink lines to correspond with those on the test. 
Head dull pale orange, sometimes rose-colour, issuing from 
the end to which the apex curves; it appears very short by 
being separated from the neck by a conspicuous circular white 
veil, or rather pavilion, with a pendent oval flap or lappet on 
each side; the neck is pale rose; the buccal disk has a ver- 
tical fissure, within which are two poimted, lnear, greenish 
corneous plates supporting the palate, through which a long, 
red-brown, narrow lingual riband passes to the cesophagus 
and stomach. The tentacula are long, white, setose, eminently 
contractile, tumid at the bases, conically tapering to a fine 
point, with eyes on very short pedicles, at their external bases. 
The foot in extension is an elongated oval, plaim-edged, white 
on both surfaces, quite plam, and destitute of papille or 
ornament around the strong fleshy pedicle. The arcuated 
