108 TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 



acutiUneattw Conrad, and Pecten parmeleel Dull. The type is fio-ured and is now 

 in the U. S. National Museum, No. 164841. 



Pliocene (lower). Crescent City, Del Norte County, Cal., south side of Light-House 

 Point, north of wharf (Diller). 



Pecten (Chlamys) bellilajiellatus n. sp. 

 PI. XLI, flgi^. 6, 6((, 7, ami la. 



Det<rrlpf!<in. — Shell averaoing- about 18 niilliuieters in altitude, about as long 

 as high, equivalve, both valves moderately convex, inequilateral; sides nearly 

 straight; margins not serrate. Right valve with 15 or 16 prominent narrow, 

 sharply convex-topped ril>s with sloping sides; interspaces much wider than 

 ribs, with narrow, flat bottoms; surface sculptured by numerous, regular, 

 equidistant, thin, concentric, imbricating lamellie. which cut squarely across the 

 l)ottoms of the intei'spaces, curve convexly toward the umbo on the sides of the 

 ribs, and loop gracefully downward away from the umbo on the tops; hinge 

 line (>qual to the length of the disk; ears equal in length; anterior ear convexly 

 truncated, separated from the disk by a deep, sharply defined, byssal notch, and 

 sculptuied by fine, regular, incremental lamelhe and five or six subequal radials; 

 posterior ear acutely pointed, radially striate, and with incremental sculpture 

 similar to but not quite as prominent as that of the anterior. Left valve similar 

 to right; anterior ear more prominently sculptured, both radially and concentrically, 

 than the posterior. 



D/'ijir/isJo/is. — Alt. is mm.; long. IS mm.; hinge line IS nnu. ; diameter 8 

 nun.; umbonal angle 1(>() . 



This species is characterized by its small size when adult, long hinge line, 

 narrow, sharply topped i-il)s and beautifully curved incremental lamelhe. It is 

 easilv distinguishable from /'. latiaurUus and varieties, wuth which it is allied, 

 by the above-enumerated characteristics. 



P. hi'llilameUatuK is so far known only from the Pliocene at Pacific Beach, 

 San Diego, where it is associated with P. Iwaleyi, P. uti-armiL etc. Type in the 

 collection of Delos Arnold. 



R.\XGK. 



Pliocene. Pacific Beach, San Diego County (Arnold). 



Pecten (Chlamys) hastatus Spwerby. 

 PI. XLI, tijr. 4; PI. XLII, fif;s. 1, la, 2, ami 2-;. 



1843. PecU-n hmlatiit: SowiTby, Thes. Conch., vol. 1, 1843, p. 72, pi. 20, tig. 236 (not of Reeve, 1852= 

 P. var. hericim (jld.; in part not of Carpenter, 1863; nor of Cooper, 1888). 



1857. Pecten alHpleclns [typ. err.] Conrad, Proc. Acail. Nat. Sci. Phila., for 1856, 1st ser., vol. 8, 

 1857. p. 313. 



1S57. Pcdeii alli/ilinttiis Conrad, Pac. R. R. Kept., vol. 7, 1857, i>. liU, pi. 3, tig. 2. 



1869. Pecten hastutm Sowerby, Gabb, Pal. Cal., vol. 2, 18(W, p. 104. 



