48 



The computor list of species common to stations occupied in this habitat 

 was very incomplete, and of little value in assessing the true nature of the 

 fauna living on rocky shores. Collecting in this environment was not at all 

 systematic, since this study was originally to be confined only to level 

 bottom areas. The species assigned to this environment with the greatest 

 significance by the computor were: the gastropods Nerita scabricosta, 

 Purpura patula pansa, Turbo fluctuosus, and Pyrene fuscata; and the 

 pelecypods, Barbatia reeveana, Isognomon chemnitziana, Ostrea conchophila, 

 Anomia adamas, and Cardita affinis californica. Anomia and Ostrea were 

 only found as dead shell within the samples, although this author observed 

 large numbers of them attached to the rocks. Actually, the above gastropod 

 species were observed to be very abundant in all rocky localities examined, 

 along with numerous chitons, patellas, neritids, littorines, and turbinids. 

 The four stations considered most indicative of this environm'ent, and the 

 portions of the shoreline inhabited by the rocky shores animals are shown 

 on fig. 14. So far, 53 living species of invertebrates have been identified 

 from the intertidal rocky shores environment, and another 18 species 

 known to live on rocky shores from the literature were also taken in the 

 vicinity of the rocks, but only as dead shell. A few of the typical mollusks 

 are figured on Plate I. Only mollusks are figured on these plates, since the 

 other invertebrates are still in the hands of the various specialists and 

 could not be photographed at the time this paper was being written. 



McLean (1961), in his list of invertebrates from Los Angeles Bay, gives 

 105 species of mollusks which occur either on the rocks or in the sand 

 among the rocks (really two separate habitats). Dushane (1962) also 

 lists 145 species of mollusks living around the rocks in a small cove at 

 Puertocitos, somewhat south of San Felipe on the west side of the Gulf. 

 Many more species were reported by these authors than were found in the 

 present study. A much larger list of intertidal mollusks can also be gleaned 

 from Keen (1958). Since this study was originally proposed as a study of 

 level-bottom faunas, this environment is discussed only briefly in order 

 that paleontologists working on fossil deposits surrounding the Gulf of 

 California and along the Pacific coast of Central and South America may 

 have some frame of reference for separating out this assemblage from those 

 assemblages which are normally found on level bottom. 



II. Intertidal sand beaches and sand flats to 10 meters. 



The waters edge of the sand beaches and adjacent sand flats to depths 

 of about 10 meters are characterized by a fauna which closely resembles 

 that found on the sand beaches and in the nearshore Gulf of Mexico as 



