50 THE WORMS. 



FIG. 53. Fixed tube-making marine worms (Serpulce). 

 VALUE. Food and bait. 



NOTE. The most brilliant light-givers are found in the families 

 Polynoida, Syllida, Chatoptcrida, and Polycirrus. If 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 071 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 " ; " Planarioe of our Ponds and Streams," E. R. 

 Lankester, in " Popular Science Review," October, 1867 ; " Alternate 

 Generation and Embryology of Antolytus 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, 



