4 THE PHYSIOLOGY OF EARTHWORMS 



amounting to 17-3% of total dry weight, and an ash residue of 9-2%. 

 These figures contrast with those of French, Liscinsky and Miller 

 (1957) who obtained figures of 6-07% and 23-07% respectively. 

 Lawrence and Millar (1945) give an even lower figure still for lipid 

 contents, 1-5% of dry weight. Table 1 summarizes the analysis as 

 known at present. 



Two smaller species, Lumbricus rubellus and Eisenia rosea have 

 a similar proportion of dry weight; 16-38% which consists of 

 61-3% protein, 17% carbohydrates, 4-5% fat and only 15% remains 

 as ash residue, and mineral salts (French, Liscinsky and Miller, 

 1957). No figures are as yet available for a fresh- water oligochaete 

 such as Tuhifex tuhifex. 



Table 1 

 Chemical Content of L. Terrestris 



Fats 



Individual classes of biochemical substances have received a 

 little attention. For example a review of the fats and sterols repre- 

 sented among invertebrates (Bergmann, 1949) included details of 

 four oligochaetes. Oil extracted from Perichaeta communissinia 

 accounts for 2-3% of the total dry weight and contains 31-2% 

 unsaponifiable material. Similar oil extracted from L. terrestris 

 contains 36-7% unsaponifiable material, L. rubellus 21-3% and 

 Tubifex tubifex 10-5%. De Waele demonstrated that cholesterol is 

 the major sterol in L. terrestris and Bock and Wette have found that 



