M. S. Laverack 
Physiology of Earthworms [PDF ebook] 
International Series of Monographs on Pure and Applied Biology: Zoology

The Physiology of Earthworms focuses on the three species of earthworms – Liimbricus terrestris, Eisenta foetida, and Allolobophora longa. Other earthworms or oligochaetes such as the fresh-water species are briefly mentioned. The topics covered include the biochemical architecture; digestion and metabolism; calciferous glands; axial field; nitrogenous excretion; water relations; respiration; physiology of regeneration; neurosecretion; nervous system; and behavior of oligochaetes. This book is a good source of information for biology students and researchers conducting work on earthworms and its different species.