ARNOLD — THE PALEONTOLOGY AND STRATIGRAPHY OF SAN PEDRO. 97 



Distinguishable by lack of sculpture. Specimen identified by Dr. Dall. 

 One specimen from lower San Pedro series of Deadman Island, which is the 

 one figured, and which is now in the collection of Delos Arnold. 



Living. — Puget Sound (Carpenter). 



Pleistocene. — San Pedro (Arnold). 



14. Leda hamata Carpenter. 



Plate XVII, Fig. 4. 



Leda hamala Cpr. , Brit. Assn. Rept., 1863, p. 644. 



Shell small, elongate-trigonal, convex, thin; umbones anterior, turning slightly toward the 

 posterior end; short, rounded anteriorly; much lengthened, narrowed and abruptly truncated pos- 

 teriorly; surface sculptured by strong, concentric raised lines; a raised band, strongly transversely 

 sculptured by continuations of the concentric ridges, passes from the umbo, around the escutcheon, 

 to the posterior end; on the interior of the posterior end is an elongated, raised process; escutcheon 

 deep-set, smooth. 



Dimensions. — Long. S mm.; alt. 5 mm.; diam. 2.5 mm.; umbo to posterior end 5.5 mm.; 

 to anterior end 4 mm. 



A small species, readily distinguishable by its long, curved posterior portion, 

 strong sculpture, smooth escutcheon, and interior posterior process. Specimen iden- 

 tified by Dr. Dall. 



A nearly perfect, united pair from the lower San Pedro series of Deadman 

 Island; rare; also reported from the Pliocene of Deadman Island. Pleistocene of 

 Spanish Bight, San Diego. The specimen figured is from the lower San Pedro 

 series, and is now in the collection of Delos Arnold. 



Living. — Santa Barbara to Catalina (Carpenter). 



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



Pliocene. — Deadman Island, San Pedro (Arnold). 



15. Leda minuta Fahr. var. praecursor, var. nov. 



Pl.\te XVII, Fig. 6. 



Shell small, trigonal, conve.x, thin; umbones anterior to middle and turning slightly toward 

 the posterior side; anterior portion from umbones short and rounded; posterior portion longer, 

 slightly depressed, produced and slightly truncated; surface sculptured by prominent, raised con- 

 centric lines; escutcheon long, narrow, slightly striated with continuation of concentric ridges; a flat 

 sculptured band runs around escutcheon from umbo to posterior end, and on the interior of the shell 

 at the posterior end of this band is a little elongate ridge or process; hinge with prominent internal 

 cartilage cup and about fifteen prominent sharp teeth on each side; pallial sinus small, narrow. 



Dimensions. — Long. 7.8 mm.; alt. 5 mm.; diam. 3.9mm.; umbo to posterior end 5 mm.; to 

 anterior end 4 mm. 



( 13 ) November 1, 19C'2. 



