Invertebrates have been used extensively in investgating the physiology of the nervous system (reviewed by Prosser, '46 and TTelsch and Schalbe, '46). It surprising, therefore, that the lipids of invertebrate nervous systems have been the subject of so few studies. Patterson, Dumm and Richards ( '45) described the lipids of the nervous system of the honeybee and recently AlcColl and Rossiter ('50) reported on the lipids of the nervous system of the squid.
Lipids have been determined in the nervous system of two invertebrate species that have been used widely in physiological rcsearch, the arachnoid king crab, I,imulus and the crustacean spider crab, Libiizia. These figures are directly comparable with those of lllccoll and Rossiter ( '50) on the nervous system of the squid, Loligo.
Methods
The niaterial was collected by one of us ( J . D. AlcC.) at the Marine Biological Laboratory, Woods Hole, during the summer of 1949. The appropriate portion of the nervous system was dissected from the fresh specimen, rapidly weighed, and placed in ethanol for dispatch to London, Canada, where the analyses were pcrformcd. The lipids were extracted and the concentration of total phospholipid, free and total cholesterol, cerebroside (glycosphingoside ) , niorioaminopliospliolipid ( phosphoglyceride ) and lecithin (phosphatidyl choline ) was determined in each