50 THE WORMS. 
Fic. 53.—Fixed tube-making marine worms (Serpu/@). 
VALUE.—Food and bait. 
NoTEe.—The most brilliant light-givers are found in the families 
Polynoide, Syliide, Chetopteride,and Polycirrus. Tf the first named is 
watched in the aquarium, gleams of greenish light will be seen at the 
attachment of each scale, and the separate organ glistens with pulsa- 
tions of light at the ruptured surface. In the second worm the under 
surfaces of the feet are the only luminous spots. In the third the light 
is confined to the dorsum of the tenth segment or joint, while the Poly- 
cirrus is phosphorescent over its entire surface, emitting a vivid pale 
bluish light. 
Works on Worms for further reference. 
Verrill, “‘ Invertebrata of Vineyard Sound,” in “ Report of United 
States Commissioner of Fisheries,” 1874; Verrill, ‘‘ Parasites of Man 
and Domestic Animals”; “ Planarize of our Ponds and Streams,” E. R. 
Lankester, in ‘‘ Popular Science Review,” October, 1867; ‘ Alternate 
Generation and Embryology of Amtolytus cornutus,” A, Agassiz, ‘‘ Bos- 
ton Journal of Natural History,” vol. vii ; “ North American Fresh- 
Water Leeches,” A. E, Verrill, in “ American Journal of Science,” 
1872, vol. iii, page 126; “Animal Parasites and Messmates,” Van 
Beneden ; “Formation of Vegetable Mold,” Darwin. 
