1-11 CAI.II'DUNIA ACAIM'-MY OF SCIENCES. 



liiiuilc not excavated, but bouiuled by ,m impicsscil liiir; liiii^c not strong; two small cardinal teetii; 

 liganieiua! area excavated, internal. 



Dimensions. — Long. 38 mm.; ah. 30 mm.; di.im. 10 mm.; Iciiglli ot limule 12 mm. 



Thi.s .<jiccic'S is (li.stiii<.;iii-iialiK' lidiii <\ iMihdlaiilmna Ciii'ixnU'r liy its [)r(mii- 

 iiuiit impre.ssed liiiuilu-bouiitlin^ liiu', roiiiulcd |i.illi:il simis, hihI Iiv its colofatioii in 

 llic liviiij:; specimens. 



llafc ill upper San Tedro series at Deadiiian Island. Altiindanl at 'I'weiity- 

 sixtii Street, >Sati Dicijo. 



Living. — Monterey to Catalina Island (Cooper): San Pedro ( Williaiu.soii). 



P k'iatocene. — San Pedro (Arnold) : San I )iego (Coo])er; Arnold). 



Pliocene. — San Die};;o well (C'oo|)cr). 



79. Callista subdiaphana Carpciiter. 



1'|..VTK XIII, Fig. 4. 



Clemenlia subdiaphana Ci'K., Brit. Assn. kept. 1S63, p. 640; Proc. Phil. Acad. Sci.,1865, p. 56. 

 Cooper, 7th Ann. Rept. Cal. St. Min., 1888, p. 235. Dai.i., Pruc. U. S. Nat. Mus., 

 Vol. XIV, 1891, p. 185, Pi. VII, figs. 5 and 6. 



Shell of medium size, oval, transverse, inequilateral, ventricose, rather thin; beaks small, 

 incurved; anterior extremity quite sharply angulated about middle of shell; posterior extremity much 

 longer and wider than anterior and very evenly rounded, projecting furthest a little below the 

 middle; ventral margin evenly arcuate; surface sculptured by numerous line, regular, concentric, 

 incremental lines; neither lunule nor escutcheon, but a faint lunul ar circumscribing line in front of 

 umbo; three prominent, shar|), cardinal teeth in each valve, the anterior one being narrower and 

 longer than the other two; external ligamental groove long, narrow; ]xdlial sinus cuneiform, rather deej). 



Dimensions. — Long. 43.5 mm.; alt. 34 mm.; diam. 26 mm ; umbo to anterior extremity 10 

 mm.; to posterior extremity 33.5 mm. 



This species is very close to Conrad's Dlnae aiignstlfnrmia from the Astoria 

 Miocene, the external characteristics of both being almost identical. Specimens 

 identified by Dr. Dall. 



Rather common in the Pliocene of Deadman Island and 'i'iram's Point. 

 Cooper's " Qiiarternary " at San Pedro inchides the Pliocene, and his specimens 

 from San Pedro were probaiily from the Pliocene. The writer has never found 

 VnHiata sabduiphana in the Pleistocene of San Pedro or vicinity. The specimen 

 fignred is from the Pliocene of Deadman Island, and is now in the collection of 

 Deles Arnold. 



Living. — South Alaska Coast to San Francisco (Dall). 



Pleistocene. — San Pedro to San Diego (Cooper). 



Pliocene. — San Diego well (Cooper): San Pedro (Arnold). 



80. Callista subdiaphana Carpenter, pedroana, var. nov. 

 I'LATK XIII, Fio. 2. 



.Shell of medium size, subelliptical, transverse, inequilateral, ventricose, rather thin; beaks 

 small, incurved; anterior extremity evenly rounded, short; posterior extremity faintly biangular. 



