GAMMARIDEAN AMPHIPODA 31 



barriers such as continents and oceanic basins, and that about one 

 sixth of the genera may be excluded by thermal barriers. At least 

 8 genera of the remaining one sixth occur in subintertidal depths of 

 California and the species of about a dozen diverse genera either have 

 not penetrated into the area or have not been collected there. One 

 may conclude that the amphipodan fauna of California is not im- 

 poverished. The transition from cold- to warm-temperate character 

 may be appreciated in table 35 by noting the confrontation or over- 

 lap of northern and southern elements. The weak representation in 

 California of several diverse boreal and tropical circumferential 

 genera apparently is characteristic of the midlatitudinal position of 

 California. For instance, Eurystheus, Lembos, Hyale, and Stenothoe 

 are diverse tropical genera which are poorly represented in California, 

 and Liljeborgia, Melita, Paramoera, and Atylus are diverse boreal 

 genera which are poorly represented in California. Families and 

 subfamilies which are poorly represented in California for unknown 

 reasons are the Dexaminidae, Phliantidae, Stenothoidae, Podoceridae, 

 and the cyproidin Amphilochidae. 



Acknowledgments 



The writer is indebted to the National Science Foundation for 

 support of this project (grant GB-586). The study was undertaken 

 while the writer was a staff member of the Beaudette Foundation of 

 Moss Landing, California, and completed with the aid and facilities 

 of the Smithsonian Institution. Mr. L. R. Hales, Jr., of the Beaudette 

 Foundation, assisted the writer with the field work and sorting of 

 the samples. Mr. Robert Campbell of Santa Barbara, California, 

 made a transit survey of sites and elevations and collected several 

 samples by means of scuba gear. Numerous students in a summer 

 course taught by the writer at the University of California, Santa 

 Barbara (1961), helped with the development of field techniques, 

 sorting problems, and data analysis. Many of the drawings were made 

 in pencil and most inked by Miss Jacqueline M. Hampton of Beau- 

 dette Foundation. Dr. Fred Clogston of California State Polytechnic 

 College, San Luis Obispo, assisted with locality selections north of 

 Pt. Conception. Mrs. Dorothy M. Halmos and her staff of the Allan 

 Hancock Library assisted the writer materially with reference prob- 

 lems. Dr. Charles R. Stasek of California Academy of Sciences 

 generously donated a suite of Allogaussia for examination. More 

 than two dozen other persons assisted with field collections, sample 

 processing, and by donating special materials to this study. Especially 

 important have been "Velero IIP' and "Velero IV" samples deposited 

 in the Allan Hancock Foundation. Much impetus and many study 

 collections were provided by Dr. John L. Mohr. The writer is grateful 

 to all persons for their aid. 



