160 CALIFORNIA ACADEMY OF SCIENCES. 



Rare in upper San Pedro series of San Pedro; one perfect right valve, which 

 is figured, is now in the collection of Delos Arnold. 



Living. — Panama; Central America (Carpenter). 

 Pleistocene. — San Pedro (Arnold). 



Genus Metis H. it A. Adams. 



Shell slightly inequivalve, suborbicular, compressed; valve sillonated; posterior flexuosity 

 submedian; no lateral teeth. 



Tellina meyeri Phil, is a characteristic species. 



103. Metis alta Conrad. 



Tellina alia Con., Jour. Phil. Acad. Nat. Sci., \'ol. VII, 1837, p. 258; (not T. alia Con., Foss. Tert. 



Form., Vol. I, No. 4, p. 41, 1833. Hanlev, Thes. Conch., Vol. I, p. 332, PI. LXII, 



fig. 200, 1847.' 

 Ltitricola alia Con., Carpenter, Brit. Assn. Rept. , 1863, p. 639; =^Arcopagia medialis Con. {fide 



Gabb, Pal. Cal., Vol. II, p. 92, 1869). Cooper, 7th Ann. Rept. Cal. St. Min., 1888, 



p. 247. Keep, West Coast Shells, p. 197, 1892. Williamson, Proc. U.S. Nat. Mus., 



Vol. XV, 1892, p. 186. 

 Metis alta Qo'ii., = Scrobicularia biangulata CvK. {fide Dall, Trans. Wagner Inst. Sci., Vol. Ill, 



Pari 5, 1900, p. 1044). 



Shell large, suboval, approaching to subcircular, ventricose, of medium thickness; beaks 

 central; anterior extremity obtusely rounded ; posterior side of the deeper valve biangulated; the 

 opposite valve with an angular groove; surface sculptured by numerous prominent lines of growth 

 and by numerous minute, radiating lines ; cartilage-pit more vertical than oblique; muscle- 

 impressions large. 



Di7ncnsions. — Long. 75 mm.; alt. 65 mm.; diam. 40 mm. 



Resembles a large, rounded, ventricose Macovia. Specimens identified by 

 Dr. Dall. 



Common in upper San Pedro series of San Pedro, and exceedingly so in the 

 Pleistocene of Los Cerrito.s, where they occur in beautifully preserved pairs. A few 

 specimens found in the upper San Pedro series at Deadman Island and Crawfish 

 George's; and in the lower San Pedro series at Deadman Island. Found in the 

 Pliocene at Pacific Beach, and in the Pleistocene at Spanish Bight, San Diego. 



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



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



riiocene. — Santa Barbara (Cooper): San Fernando (Cooper; Arnold): Sau 

 Diego (Arnold). 



Miocene. — Monterey; El Toro Ranch, Monterey County (Cooper). 



Genus Macoma Leach. 



Shell without lateral teeth, usually subtrigonal and with a marked ])osterior flexure; the 

 surface feebly scul])tured concentrically, or smooth; the siphons naked. 



Type, M. tenera Leach. 



