9 



8 HABITS OF WORMS, Chap. I. 



. 



CHAPTER I. 



HABITS OF WORMS. 



Nature of the sites inhabited — Can live long under water — 

 Nocturnal — Wander about at night — Often lie close to the 

 mouths of their burrows, and are thus destroyed in large 

 numbers by birds — Structure — Do not possess eyes, but can 

 distinguish between light and darkness — Retreat rapidly when 

 brightly illuminated, not by a reflex action — Power of attention 

 — Sensitive to heat and cold — Completely deaf — Sensitive to 

 vibrations and to touch — Feeble power of smell — Taste- 

 Mental qualities — Nature of food — Omnivorous — Digestion — 

 Leaves before being swallowed, moistened with a fluid of the 

 nature of the pancreatic secretion — Extra-stomachal digestion 

 — Calciferous glands, structure of — Calcareous concretions 

 formed in the anterior pair of glands — The calcareous matter 

 primarily an excretion, but secondarily serves to neutralise the 

 acids generated during the digestive process. 



Earth-worms are distributed throughout the 

 world under the form of a few genera, which 

 externally are closely similar to one another. 

 The British species of Lumbricus have never 

 been carefully monographed; but we may 

 judge of their probable number from those 

 inhabiting neighbouring countries. In Scan- 

 dinavia there are eight species, according to 



