26 



105 for Acila castrensis (small clam) and 98 for Mjtrella 

 carinata ( snail) » Another haul north of Anacapa Island 

 had no less than 59 specieso The other kinds of animals 

 in these hauls were not named. 



Illustrated faunal handbooks and keys for ready 

 identification of the invertebrate animals of southern 

 California are greatly needed in attempting a study of 

 many of these groups of animalSo Many are still unknown 

 or unrecordedo Until these needs are supplied, studies 

 of other kinds will not only be discouraging, but im- 

 possible. 



Ecological Classification of Faunal Units 



A systematic classification is an expression of 

 genetic differences between the various faunal units 

 and therefore expresses progressive degrees of develop- 

 mental similarity or relationshipo An ecological classi- 

 fication, on the other hand, is an expression of degrees 

 of social integration, of adaptational modifications and 

 adjustments to environmental factorSo This results in 

 grouping organisms according to unrelated phenomena, 

 such as the kinds of sediments they inhabit, the character 

 of the food they eat, the levels of temperature or light 

 tolerances, and other factors of external origin^ 



Although ecological classification has no phylogenetic 

 significance, it is valuable to recognize groups or 

 associations of animals, which may have indicator value, 



