164 JOURNAL OF ENTOMOLOGY AND ZOOLOGY 



is their service to remove the waste of ocean life. The latter are 

 free swimmers and in their wanderings scour the surface of the 

 waters. The former usually remain close in their native haunts 

 and it is they who purify the substrata of the sea. Not here 

 does their service end. So abundant are they that they form a 

 part of the food of many fish and thus they are indirectly food 

 providers for men. To these ends the Isopoda are very widely 

 distributed. They are most abundant in the northern waters. 

 Thence they extend in varying numl)ers to the warm southern 

 waters and the temperate shores and from east to west. So 

 great is their importance that we dare not speculate as to the 

 state of unstable equilibrium in nature which their sudden and 

 thorough destruction would cause. Suffice it to say, that at 

 present no such calamity is pending, for the isopods are a 

 mighty throng and well equipped by nature to survive. 



In the studies which follow I have described and illustrated 

 twelve species collected at Laguna Beach, California, in the 

 summer of 1911. One of these is a new species, two are new 

 varieties. A number of the others, although noted before, have 

 not been illustrated at all before or if so not at all completely. 



List of the Species Represented in this Study 



Superfamily FLABELLIFERA 



A. Family CTROLANID.E 



Genus Cirolana 



Cirolaiia Jiarfurdi (Lockington) 



B. Family SPH^ROMID^ 



Genus Dynamene 



Dynamene glabra Richardson 

 Superfamily VALVIFERA 

 A. Family IDOTHEIDyE 



a. Genus Idothea 



Idothca rcctUinca (Lockington) 



b. Genus Pentidotea 



