EARTHWORMS. 9 1 



Most of these worms are oviparous ; a few produce living 

 young ; the majority are hermaphrodites, the testes being paired. 

 The development is often direct ; the eggs are laid in patches or 

 cocoons, and give origin direct to young worms. 



A larval form is, hovyever, found in some marine species 

 {CJicetopoda) known as Levin's Larva, whose growth resembles 

 in many respects the growth of a scolex into a Tapeworm. 



Segmented worms move by two different processes : (i) by 

 simple or grouped setse or bristles placed in the cutis, Earth- 

 worms, &c. (Oligochceta), and (ii) by terminal suckers {Hiru- 

 dinea). 



ReprodwMon may be asexual, by fission and by gemmation 

 in the long axis (Okcetopoda). As a rule, it is sexual, when the 

 worms may be hermaphrodites (Oligochceta, Hirudinea) or of 

 separate sexes {Marine Chcetopoda). The food very largely 

 consists of animal matter ; at other times, as in the Earth- 

 worms, of decaying vegetation. 



Earthworms (Lumbrici). 



The Earthworms belong to the Chsetopod group Oligochcdn; 

 which are characterised by being terrestrial, having no parapodia, 

 but setfe as organs of locomotion ; no oral armature, cirri, ten- 

 tacles, or branchiae. They are hermaphrodites, and develop 

 direct. 



The Oligochaetse are again divided into (a) the Terricolce, or 

 true earthworms, with nephridia in the genital segments ; and 

 (b) the Limicolce, or water-worms, which have no nephridia in 

 the genital segments (Naidce). 



Life-history of the Earthicorm (Lumbricus terrestris). — The 

 eggs of the earthworm are laid in heaps or capsules in the 

 ground. In one or two weeks these white transparent eggs give 

 rise direct to young Lumbrici, which are at first soft, but as they 

 grow they obtain a compact skin armed with setse in simple pits 

 and have red blood. Eyes are never present, yet worms are very 



