42 



THE PHYSIOLOGY OF EARTHWORMS 



O'Brien (1957a) also subjected the body of two species, E.foetida 

 and O. cyaneum, to analysis for various metabolic substances. He 

 found, for example, that the distribution of glycogen in the 

 muscular body wall (average 4-5 mg/g wet weight) which was low in 

 the region of segments 36-55 was the mirror image of the distri- 

 bution of glycogen in the intestinal tissue (average 7-0 mg/g wet 

 wt.) which had an extended peak in the same area. Lipoid materials 

 (3-4 mg/100 mg wet wt. in the whole worm) show a maximum in 

 the middle part of the body, probably due to the intracellular 

 absorption of lipoid into the intestinal epithelium and eleocytes 

 (Fig. 15). 



Table 6 



Effect of Regeneration on the Respiratory Rates of Areas of 

 THE Body of A. longa (/xl./lOO mg wet wt.) (From O'Brien, 



1947) 



The production of lactic acid, reflecting the glycolytic activity 

 of the tissues, shows a U-shaped curve, and succinoxidase activity 

 of body wall and granules prepared by centrifugation also show 

 greater values in preparations from anterior and posterior regions 

 than in mid-body. 



These later experiments involved homogenates and not con- 

 tinuous tissues so it is improbable that muscular movement can 

 account for regional differences. Unfortunately once again the 

 temperature at which these experiments were run was near the 

 upper thermal death point, 27 °C, and this may have had some 

 effect. The greater concentration of functional organ systems at 

 the anterior end, in the shape of gut specializations, sex organs and 

 nervous concentrations may all serve to increase metabolic reactions 



