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On new Shells from Mauritius and California. — 2. 
XXXIX.—Descriptions of new Species of Shells from 
Mauritius and California. By EpGar A. SMITH. 
Pecten Crouchi. 
Testa compressa, inferne rotundata, ad apicem peracuminata, sub- 
eequivalvis, costis validis octo in utraque valva instructa, supra 
et inter costas radiatim striata, undique microscopice superficial- 
iter reticulata ; valva sinistra albida, aurantio vel purpureo plus 
minus tincta, supra et inter costas saturate purpureo vel san- 
guineo irregulariter copiose maculata, lineisque angulatis albis 
inter costas hic illic ornata; valva dextra pallidior, marginem 
ventralem versus aurantio vel purpureo tincta, inter et supra 
costas parum maculata; margo cardinis perobliquus, rectilinearis, 
valde inequalis, parte postica brevissima, longit. totius 3 vix 
eequante ; auriculee valde ineequales, radiatim tenuiter costulatie, 
postica minima, antica valve dextre inferne profunde sinuata ; 
cost valve sinistre interstitiis angustiores, valve dextra 
latiores. 
Longit. 38 millim., alt. 46, diam. 11. 
lab, Mauritius. 
This beautiful species is distinguished by the very sloping 
dorsal margins, which converge at the apex at an angle of 
75° ; the very unequal auricles; the elevated ribs, those of the 
left valve being narrower than 
the interstices or the coste of 
the other valve; the style of 
coloration, which, however, is 
variable ; the fine radiating stric 
and the microscopic reticulation 
or shagreened epidermal coating, 
which everywhereinvests the sur- 
face and which is easily rubbed off 
during the process of cleaning. 
The central ribs of the left valve 
have about seven raised lines down 
each, separated by striz or sulci 
of about equal width, and the 
grooves between the coste are 
ornamented with about the same 
number of lines. ‘The valves 
are whitish within, and, being thin, the blotching of the 
exterior, especially that of the left valve, is more or less 
distinctly visible. 
This species differs from P. tigris, Lam., which in some 
