CLASS PELECYPODA 
51 
Ostrea palmula Carpenter, 1857. 
Masatlan Catalogue , p. 163. 
O. ? conchaphila, t. satis magna, margine subito ascendente, valva 
inferiore superante, undulato, limbo purpureo sett olivaceo irregulariter 
tessellato; linea pustularum valva superiore, in parte nacrea, a margine 
remota, circumeunte, in puncta convenientia valva inferiore aptante; 
pagina interna subnacrea, aurantio seu purpureo tincta; rarissime spinis 
ramosis paucis, tabulis ad marginem exteriorem arborescentibus. Length, 
2.3; lat., 1.6; alt., .54 inches. (Carpenter.) 
Remarks by P. P. Carpenter: Remarkable for the palmated foliations 
in the outer margin, which has a distinct limb mottled with purple and 
olive; and for the row of denticles within this limb and within the nacreous 
border, fitting into corresponding depressions in the other valve. As these 
seem to appear only in the adult shell, it is barely possible that 0. con¬ 
chaphila may occasionally develop itself into this form. 
Type in Liverpool Collection. Type locality, S. W. Mexico. 
Range. Puget Sound to Cape San Lucas, Lower California. 
Family PECTINIDZE. 
Genus PECTEN Muller, 1776. 
Shell suborbicular, regular, resting on the right valve, usually orna¬ 
mented with radiating ribs; beaks approximate, eared; anterior ear most 
prominent; posterior side a little oblique; right valve most convex, with a 
notch below the front ear; hinge-margin straight, united by a narrow 
ligament; cartilage internal, in a central pit; adductor impression double, 
obscure; pedal impression only in the left valve, or wanting. (Tryon. 
S. S. Conch.) 
Type. Ostrea maxima Linn. 
Distribution. World wide, Nova Zembla to Cape Horn. 
Range in Time. Devonian to the present. 
Subgenus Pecten s. s. 
Pecten diegensis Dali, 1898. 
Plate 29, fig. 5, and plate 41, fig. 3. 
Pecten fioridus Hinds, Zool. Sulph. Voy., p. 60; pi. 17, fig. 6 (1844). Not Ostrea 
( Pecten ) fioridus Gmelin (1792). 
Shell rather elongately ovate, equilateral, inequivalve; valves com¬ 
pressed, concentrically finely striated, rayed with 18 ribs; left valve flat, 
slightly convex in the middle, with the ribs much raised, narrow, angled 
in the middle; right valve convex, with the ribs much raised, prominent, 
