1915] 



Clark: Fauna of the San Pablo Group 



467 



a considerable angle ; also, the anterior lateral is longer and heavier 

 on the former. Other differences are seen in the comparison of the 

 hinge plates of the two species. 



Named in honor of Dr. W. H. Dall of the Smithsonian Institution. 



Dimensions. — Type specimen : height, 57 mm. ; length, about 56 

 mm. Height of co-type (pi. 50, fig. 2), about 70 mm. 



Occurrence. — From the Upper San Pablo Group, University of 

 California locality 38. 



Found in association with Astrodapsis ivhitneyi, Macoma secta, 

 Mytilus trampasensis, Solen perrini, Venus martini, Mulinia pabloensis, 

 Neverita pabloensis, Trophon carisaensis. 



PITAEIA BEHRI, n. sp. 

 Plate 54, figures 2, 3, and 4 



Shell subtrigonal in outline; beaks prominent, strongly incurved; 

 lunule large, depressed and slightly wider in right valve than in left. 

 Anterior dorsal edge short and rather deeply concave ; posterior dorsal 

 edge nearly straight, about twice as long as the anterior dorsal edge ; 

 ventral edge strongly arcuate ; posterior and anterior ends evenly 

 rounded. Surface of shell rather strongly depressed along the pos- 

 terior dorsal margin, but there is no well-defined line separating this 

 narrow depressed area from the remaining portion of the shell. Sur- 

 face of shell sculptured by somewhat irregularly spaced, sharp, con- 

 centric lamellae. Posterior cardinal long and narrow, middle cardinal 

 heavy and high; anterior cardinal thin, not so high as middle cardinal; 

 anterior lateral prominent. Hinge plate of right valve not known. 



This species somewhat resembles in outline Cytheria cliabloensis 

 Anderson, 40 from which it differs in the following respects : It does 

 not have so prominent ribbing ; the hinge plate as compared to Ander- 

 son 's figure is different. 



Named in honor of Mr. Ernest Behr, the collector of the specimen 

 described. 



Dimensions. — Type specimen: height, 62 mm.; width, about 7(1 

 mm. ; diameter of both valves, about 37 mm. 



Occurrence. — In the upper part of the Lower San Pablo Group on 

 San Pablo Bay, associated with Dosinia merriami, n. sp., Pitaria 

 stalderi, n. sp., Chrysodomus pabloensis, n. sp., Ficus, cf. stanfordensis 

 Arnold, University of California localities 1279, 1532, and 1600. 



*» Anderson, F. M., "A stratigraphic study in the Mount Diablo Range of 

 California," Proe. Calif. Acad. Sci., 3rd Series, vol. 2, no. 2, p. 1960, pi. XVII, 

 figs. 83-85. 



