10 U.S. NATIONAL MUSEUM BULLETIN 258 



tions of the coastal intertidal cannot be calculated from those data 

 because the sampling of substrates in the Phyllospadix-pelvetiid zone 

 has been emphasized. 



More than 155 species of Amphipoda, including those 118 species 

 reported herein are now known to occur in the Californian intertidal 

 (Appendix II). Nineteen of the species, requiring the erection of 4 

 genera, are new. Although more than a sixth of a million specimens 

 has been processed in this survey, a surprisingly large number of 

 species is rare (those having been collected as fewer than 10 speci- 

 mens). Undoubtedly, numerous special habitats and niches remain 

 unsurveyed. The unexpected divergence of amphipodan faunas at 

 localities such as Pt. Dume and Goleta is evidence of the need for 

 more detailed examination of additional localities. Study of specific 

 habitats and ectocommensal relationships, utilization of screening 

 devices with even smaller meshes, and the careful identification of 

 juvenile stages are other desiderata for future studies. 



Gridworks in the Phyllospadix-pelvetiid zones. — Gross field obser- 

 vations have shown that these zones vary greatly from locality to 

 locality. The dissimilarity in densities and kinds of flora, differences 

 in degree of slope and therefore the width of the zone, the degree of 

 exposure to surf, and the variable occurrence of sands all are reflected 

 in the amphipodan faunas. In one grid at Carmel Point (48-A-E, 

 table 3) the fauna is dominated numerically by Oligochinus lighti, 

 with Hyale grandicornis and Allorchestes anceps next in rank, followed 

 by low frequencies of Hyale rubra frequens. In a neighboring gridwork 

 (table 4) Hyale rubra frequens is the most abundant species but it is 

 nearly equalled by Elasmopus rapax mutatus and is followed in rank 

 by Photis (cf. bifurcata) and Aoroides columbiae; Oligochinus lighti is 

 a poor fifth in frequency and Hyale grandicornis and Allorchestes 

 anceps are absent. In comparison with the Phyllospadix-pelvetiid zone 

 at Cayucos, reported below, the sites at Carmel are impoverished; 

 one of the sample grids at Carmel (table 3) yielded only 9 species of 

 Amphipoda and the other (table 4) only 17 species. Other samples of 

 Phyllospadix and algae are described in tables 5 and 6 in order to 

 demonstrate a greater diversity to the fauna at Carmel than shown 

 just by the gridworks of tables 3 and 4. 



The Phyllospadix-pelvetiid zone at Cayucos seems as well developed 

 and diversified as any observed between Monterey and La Jolla. 

 Nevertheless, it is similar to most other sample grids of the zone at 

 other localities because of the high frequencies of Hyale rubra frequens, 

 Aoroides columbiae, Photis brevipes and Calliopiella pratti (table 7). 

 A total of 47 species of Amphipoda has been collected in the sample 

 grid (Appendix I). A contributing factor to this diversity is the strong 

 intermixture of northern and southern species: northern Calliopiella 



