ARNOLD — THE PALEONTOLOGY AND STRATIGRAPHY OF SAN PEDRO. 159 



Shell of nicdiuni size, ovate-triangular, moderately elongate, compressed, thin; beaks sub- 

 central, small, pointed, prominent; anterior extremity evenly rounded; posterior dorsal slope steeper, 

 rectilinear, obliquely truncate at its termination; ventral margin moderately incurved at flexure, 

 which is narrow, but well marked, and extends out into a prominent beak at the extremity of the 

 shell; a prominent, narrow, submarginal, flexural ridge extends from beak to posterior extremity; 

 surface sculptured with numerous, regular, sharp, elevated, concentric, incremental lines; hinge area 

 broad and strong; one prominent cardinal tooth in each valve, which is bifid in right valve; one 

 anterior lateral in right valve; ligamental area prominent, long; pallial sinus very large, extending 

 nearly to anterior adductor scat;. 



Dimensions. — Long. 62 mm.; alt. 37 mm.; diam. 10 mm. 



Distinguishable from 7'. bodcgensis by largef, broader shell, more centi'al, less 

 curved beaks, much more prominent flexural ridge, posterior beak and incurved base 

 line, much stronger, broader hinge, and much larger pallial sinus. Distinguishable 

 from ?'. rubescens by more extended, beaked posterior extremity, flexural ridge, 

 straight beaks, and much stronger hinge, especially in the ligamental area. Speci- 

 mens identified by Dr. Dall. 



One valve found in the upper San Pedro series at Los Cerritos, which is 

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



Living. — Catalina Island, IG to 38 fathoms, young (Dall): San Pedro Bay; 

 Long Beach (Shephard). 



Pleistocene. — San Pedro (Arnold). 



102. Tellina (Angulus) rubescens Hanley. 



Platk XV, Fig. 9. 



Tellina rubescens Hanl., Carpenter, Brit. Assn. Rept., 1856, p. 302. 



Shell of medium size, ovate-triangular, compressed, thin; beaks posterior, small, sharp, 

 turned toward the rear; anterior dorsal margin evenly but slightly arcuate to near extremity, where 

 it turns off quite abruptly, giving an evenly rounded end, which is most produced below the middle; 

 posterior dorsal slope steeper, rectilinear; posterior extremity truncated, with a rounded right angle 

 at base; basal margin nearly rectilinear from posterior angle to within one-third length of shell from 

 anterior end; a prominent angular ridge extends from beak to posterior basal angle; surface sculp- 

 tured by regular alternating concentric bands and distinct sulcations; sculpture less regular posterior 

 to angular ridge; hinge-area small; right valve with two cardinal teeth, posterior one bifid; one 

 posterior lateral tooth at lower end of ligamental area in right valve; pallial sinus large, arcuate 

 upwards near middle and extending nearly to anterior adductor scar. 



Dimensions. — Long. 43 mm.; alt. 26 mm.; diam. 10 mm.; beak to anterior extremity 

 23 mm.; to posterior extremity 20 mm. 



Distinguishable from T. bodegensis by much broader shell, less oblique trunca- 

 tions, greater convexity, more regular and coarser sculpture, stronger hinge, posterior 

 lateral tooth, and much larger pallial sinus, which extends almost to anterior adduc- 

 tor. Distinguishable from 7'. idft: by less produced and unflexed posterior portion, 

 ba.sal posterior angle, and rectilinear ventral margin, weaker hinge, and posteriorly 

 bent beaks. This species .seems to lie between T. idm and 7\ hodegensii^ in many 

 respects, having the large sinus of the one and the general, though much broader, 

 outline of the other. Specimen identified by Dr. Dall. 



