58 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
Pecten latiauritus fucicolus Dali, 1898. 
Traits. Wagner Free Inst., 3:710. Zool. Sulphur Voy. Moll.; pi. 17. 
Shell moderately compressed, smooth, concentric sculpture obsolete; 
ribs low, rounded, wide, entire; hinge line shorter than in the type, and 
without any sinus between the posterior ears and the disk. Length, 30; 
height, 31 mm. (Dali.) 
Type in U. S. N. M. Type locality, Santa Barbara, California. 
Range. Santa Barbara, California, to Cape San Lucas, Lower 
California. 
SECTION PLAGIOTENIUM Dali, 1898. 
Pecten circularis Sowerby, 1836. 
Proc. Zool. Soc., p. 110. Thes. Conch. Pecten; pi. 15, figs. 105, 106. 
Shell globose, very ventricose, equilateral, inequivalve, valves, right 
the more convex, rayed with 18 smooth strong ribs, of which the inter¬ 
stices are excavated; ash white, stained and variegated with grayish black; 
ears equal. (Conch. Iconica.) 
Pect. testa suborbiculari, tumida, subasquivalvi, sequilaterali, fusco 
alboque varia, auriculis magnis, subaequalibus; costis radiantibus octo- 
decim interstitiis latioribus, arcuatim striatis; valva altera sulcis profundi- 
oribus. Long., 1.5; lat., 0.8; alt., 1.4 poll. (Sowerby.) 
This is the species that has been called P. ventricosus Sowerby, but 
that species comes from St. Elena, and young specimens were brought 
by Mr. Cuming from Calapan, Philippines. (Sowerby.) 
Type in Museum Cuming. Type locality, ad Sinum Californise. 
(Guaymas.) 
Range. Monterey, California, to Payta, Peru. 
Pecten circularis asquisulcatus Carpenter, 1865. 
Plate 42, figs. 1, 2. 
Ann. Mag. Nat. Hist. (3) 15:179. Arnold, Tert. Pectens Cal.; text figs. 1, 2; pi. 
50, fig. 1. 
P. testa P. ventricoso simili, sed tenuiore, minus ventricosa; costis 
pluribus angustioribus xx.-xxi.; interstitus (prascipue valva superiore) 
fere aequalibus; auriculis magnis productis, acutis; sinu serrato; testa jun, 
interstitiis alte insculptis, laminis concentricis crebris, vix extantibus, 
interstitia, costas auriculasque transeuntibus. Long., 3.2; lat., 3.35 ; alt., 1.5. 
This is intermediate between the tropical P. ventricosus and the 
Atlantic P. irradians. (Carpenter.) 
P. var. czquisulcatus varies from the typical P. circularis, by its larger 
size when adult, flatter and thinner disk, narrower ribs, and more subdued 
coloration. ( Arnold.) 
