112 CAI.IKOltNIA ACADI'MY OF SriF.NCKS. 



Tliis is the type form and is distingiiisliiihlc hy acutely pointed ears, distinct, 

 sqnarisli ribs and wide .slieli. Specimens identified by Dr. Dall. 



Common in upper San IVdro series of San Pedro, Los Cerritos, Crawfish 

 (Jeorge's, Deadman Island, San IVdro, and Lonic Heaeli; rare in lower San IVtlro 

 series of Deadman Island and San Pedro. Found al.so at Spanish Blight and Twenty- 

 sixth Street, San Diego. The specimen figured is from the upper San Pedro series 

 at San Pedro, and is now in the collection of Delos Arnold. 



Living. — Santa Barbara to San Diego (Carpenter). 



Pkititnccuc. — Santa Barbara; San Pedro (Cooper) : San Pedro (Arnold) : San 

 Pedro; San Diego (Dall): San Diego (Arnold). 



32. Pecten (Chlamys) latiauritus Cun., var. fragilis, var. nov. 



I'l-ATK XII, Fig. 8. 



Shelf of same general type as P. latiatirittis. More compressed and much thinner; ribs 

 seven to nine, very low and rounded, with shallow, rounded inters])aces; surface smooth, the 

 concentric sculpture being nearly obsolete ; hinge long, ears sharply pointed. 



Dimensions. — Long. 26 mm.; alt. 26 mm.; diam. 78 mm.; hinge 25 mm. 



Distinguishable from var. jiiicicolus Dall, which it resembles, by having a 

 longer hinge-line and pointed ears. 



Kare in upper San Pedro series of San Pedro and Los Cerritos. The speci- 

 men figured is the type, which is from the upper San Pedro series at San Pedro, and 

 is now in the United States National Museum. 



Pleistocene. — San Pedro (Arnold). 



33. Pecten (Chlamys) latiauritus Con., var. monotimeris Con. 



Plate .\II, Figs. 4 and 4a. 



PecUn monotimeris CoN., Jour. Phil. Acad. Sci., Vol. VII, 1837, p. 233, PI. XVIII, fig. 10. Carpenter, 

 Brit. A.ssn. Rept., 1863, p. 645. Cooper, 7th Ann. Rept. Cal. St. Min., 1S88, p. 257. 

 Keep, West Coast Shells, p. 167, fig. 140, 1892. 



Pecten latiauritus \zx . w(7«(7//w^r/5CoN., Dall, Trans. Wagner Inst. Sci., Vol. Ill, Part 4, 1898, p. 709. 



Shell resembling P. latiauritus, but more oblique, inflated, and markedly shorter, with 

 smaller ears. 



Dimeiisions. — Long. 19 mm.; alt. 20 mm.; diam. 9 mm. 



Rare in lower San Pedro series of Deadman Island and San Pedro, and in 

 upper San Pedro series of Los Cerritos, San Pedro, Long Beach, and Crawfish 

 George's. Found also in Pleistocene of Spanish Bight, San Diego, and Barlow's 

 ranch, Ventura. The specimen figured is from the upper San Pedro series at San 

 Pedro, and is now in the collection of Delos Arnold. 



Living. — Santa Barbara to San Diego (Dall). 



Pleistocene. — Santa Barbara; San Pedro (Dall): San Pedro; San Diego; 

 Ventura (Arnold). 



