GAMMARIDEAN AMPHIPODA 9 



mal records of the California Cooperative Fishery Investigation 

 (CalCOFI) and unpublished records deposited in the Allan Hancock 

 Foundation (from California Water Pollutional Survey studies) off- 

 shore sea temperatures returned to relatively normal ranges after 

 1960. The possible fluctuations in faunal composition and densities 

 of species at Cayucos in relation to inshore thermal values would be 

 information of use in determining whether a few type areas could 

 be established for monitoring small changes in thermal environment 

 by periodic faunal diagnoses. Perhaps organisms are better sensors of 

 slight environmental changes than are human instruments. 



The absence of some southern species at Corona del Mar, in con- 

 trast to their presence at the more northerly Cayucos site, may be 

 the result of human interference with the environment and should be 

 investigated. 



If the warm-temperate northeastern Pacific region is definable as 

 that coast between Bahia Magdalena, Baja California, and Pt. Con- 

 ception, California (Garth, 1955), then the use of Corona del Mar as 

 a descriptive base may be disadvantageous because of its northerly 

 situation in the region. On the other hand, it is one of the few rocky 

 intertidal areas of the 1100 km. coast that is not presumed to be under 

 the influence of upwelling. Most of the Calif ornian rocky intertidal 

 occurs on projecting headlands; cold-temperate organisms are known 

 to be distributed discontinuously southward on these headlands. 

 Most of the headlands presumably would be unsuitable for the de- 

 scription of a warm-temperate provincial faunal type. The only other 

 locality, known to the writer through personal observation, which 

 might be suitable as a descriptive base is a 30 km. length of coast 

 east of Punta Eugenia (east of Cedros Island, Baja California). How- 

 ever the fauna there is known to have two conspicuously different 

 species not recorded from the mainland of California (J. L. Barnard, 

 1952b, 1952c). Those species have strong tropical affinities and may 

 be representatives of an isolated tropical fauna. 



The Amphipodan Fauna 



This analysis is based on those quantitative and non-quantitative 

 samples summarized in tables 3-25 and all samples described in full 

 detail in Appendix I. Various samples not otherwise discussed are 

 also included in Appendix I; they have unique combinations of species 

 or new records. 



As much of the data as possible have been collected with crude 

 quantitative methods to provide information on frequencies of 

 species (table 2). Those frequency data are to be used primarily as 

 relative information within specific localities. Accurate total popula- 



