The polyphosphoinositides and other lipids of peripheral nerves.

1. A detailed lipid analysis of the peripheral nerves of the crab (claw, leg), lobster (claw, leg), cow (splenic), hen, rabbit, sheep and monkey (sciatic) is presented. 2. The so-called ;myelinic lipids', cholesterol, sphingomyelin, ethanolamine plasmalogen and phosphatidylserine, occurred in the highest proportion in the lipids of vertebrate myelinated nerves, whereas the percentage of lecithin was greatest in the lipids of non-myelinated nerve fibres of both vertebrates and invertebrates. 3. Triphosphoinositide was found in all nerves examined and its concentration in the extracted lipids supports the concept that it is predominantly localized in the myelin sheath. 4. In crustacean nerve 12-14% of the phospholipids was in the form of alkyl ether phospholipids, which in the lobster were approximately half choline-containing and half ethanolamine-containing.