164 CALIFORNIA ACADEMY OF SCIENCES. 



io8. Macoma nasuta Conrad var. kelseyi Ball. 



Mdcoma kelseyi Dall, Trans. Wagner Inst. Sci., Vol. Ill, Part 5, 1900, p. 1052, PI. XLIX, fig. 7. 



Shell of medium size, elongate-ovate, compressed, thin; posterior extremity cuneiform, 

 obliquely truncated much above ventral margin; umbones nearly central; other characteristics 

 same as in M. 7iasuta. 



Dimensions. — Long. 70 mm.; alt. 45 mm.; diam. 18 mm.; umbo to anterior end 31 mm.; to 

 posterior end 39 mm. 



Distinguishable from other species by same characteristics that distinguish 

 M. nasuta; distinguished from M. naauta by narrower, Hatter shell, and more oblique 

 truncation of posterior end. Specimens identified by Dr. Dall. 



Rare in the upper San Pedro series at San Pedro and Los Cerritos. Found 

 also in the Pleistocene at Twenty-sixth Street, San Diego. 



Living. — San Diego and south (Dall). 



Pleistocene. — San Pedro; San Diego (Arnold). 



109. Macoma secta Conrad. 

 Plate XVI, Fig. 5. 



Tellina secta Con., Jour. Phil. Acad. Sci., Vol. VII, 1837, p. 257. Hanley, Thes. Conch., p. 337, 

 PI. LXV, figs. 245, 248, 1847. 



Macoma sec/a Con., Carpenter, Brit. Assn. Rept., 1863, p. 639. H. & A. Adams, Gen. Rec. 

 Moll., p. 401, 1858. = Telli?ia ligamettlina D¥.sn. {Jide Gabb, Pal. Cal., Vol. II, p. 73, 

 1869). Cooper, 7th Ann. Rept. Cal. St. Min., 1888, p. 249. Keep, West Coast Shells, 

 p. 191, fig. 163, 1892. Williamson, Proc. U. S. Nat. Mus., Vol. XV, 1892, p. 185. 



Macoma {Rexithcerus') secta Con. = var. edulis (Nutt. mss.) Cpr. (fide Dall, Trans. Wagner Inst. 

 Sci., Vol. Ill, Part 5, 1900, p. 1053). 



Shell large, suboval, slightly ventricose, rather thin; umbones subcentral, evenly rounded 

 anteriorly; posterior end truncated obliquely much above the base line; posterior dorsal margins 

 short, straight, sloping off quite steeply to angle where it meets line of truncation; fold prominent ; 

 surface sculptured bylines of growth; two cardinal teeth in each valve; ligament short, thick, inserted 

 on an elongated, oblique, rib-like callus; margin beneath the gape appearing as if cut or broken; 

 pallial sinus large, expanded within, not reaching to anterior muscle-impression. 



Dimensions. — Long. 82 mm.; alt. 65 mm.; diam. 24 mm. 



Distinguishable by large size, broad shell, subcentral umbones, equal convexity 

 of valves, and the prominent short ligamental callus. Resembles a Mactra somewhat 

 in outline. Specimens identified by Dr. Dall. 



Found in the lower San Pedro series at Deadman Island and San Pedro; and 

 in the upper San Pedro series at Deadman Island, Los Cerritos, Crawfish George's, 

 San Pedro, and Long Beach. Found also in the Pleistocene at Spanish Right, 

 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. — Bodega Bay to San Diego; Japan (Cooper). 



Pleistocene.— ^ani-A Barbara to San Diego (Cooper) : San Pedro; San Diego 

 (Arnold). 



Pliocene. — Santa Barbara; San Fernando (Cooper). 



