534 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. [1885. 



NOTES ON THE MOLLUSKS OF THE VICINITY OF SAN DIEGO, CAL., 

 AND TODOS SANTOS BAY, LOWER CALIFORNIA. 



By CHARLES R. OBCUTT,* with continents by W. H. DALL. 



Daring the past few years I have made extensive collections, mainly 

 of littoral shells, in this vicinity, and have had opportunity for making 

 hasty notes and collections while botanizing on the shores of All Saints 

 (Todos Santos) Bay, situated about 50 miles south of San Diego. From 

 material collected, the marine fauna of San Diego appears to possess a 

 larger number of the species of the Lower Californian coast than of the 

 Californian province to the north, while few species can be considered 

 as locally characteristic with our present knowledge of their distribu- 

 tion. 



San Diego Bay is protected on the west by a high promontory, Point 

 Loma, with a rocky ocean beach and a shingle beach by the entrance 

 to the harbor. Inside of the entrance is an extensive bed of clay and 

 boulders at what is known as La Pl&ya, and this station forms the prin- 

 cipal home of the pholads, rock pectens (Hinnites gigantea Gray), and 

 other shells not elsewhere found abundantly. The bay is protected on 

 the southwest by a low, narrow peninsula, with a hard, sandy ocean 

 beach, and sand or mud on the bay side. North of San Diego Bay lies 

 a large lagoou known as False Bay, which possesses extensive muddy 

 flats and a narrow peninsula of sand dunes on the west. Inside of this 

 bar is a stretch of rocky beach, famous as a clam bed, and to this refer- 

 ence is usually made when False Bay is mentioned. North of the ocean 

 side of this peninsula the beach is similar to that on the west of Point 

 Loma, rocky pools with irregular stretches of flat or broken boulders 

 partially imbedded in shell sand, beneath which a rich harvest of small 

 species may be anticipated. 



Todos Santos (or All Saints) Bay is unprotected from the surf, and 

 on the north and south possesses rocky beaches, between which on the 

 east lies about 20 miles of hard, sandy beach, poor in living shells. The 

 north beach is of a volcanic formation, while on the south it is largely 

 composed of fossil shells, of which there is an immense deposit. When 

 the station is not mentioned, the species has been found at both San 

 Diego and on Todos Santos Bay. The determinations have largely been 

 made or verified by George W. Try on, jr., of Philadelphia, and William 

 H. Dall, of Washington, to whom I am greatly indebted. Specimens of 

 the more interesting species have been contributed to the United States 

 National Museum and the Museum of the Academy of Natural Sciences 

 at Philadelphia. 



* The specific nomenclature of this paper has been revised by Mr. W. H. Dall at Mr. 

 Orcutt's request ; the rarer species have been examined, and several doubtful species 

 have been determined by Mr. Dall from the types in the National Museum. Occasional 

 notes in brackets have also been added by Mr. Dall. 



