220 THE WORMS 



CLASSIFICATION OF SEGMENTED WORMS (ANNULATA) 



CLASS I. Chaetopoda (bristle-footed). Segmented worms having setae. 



SUBCLASS I. Polychceta (many bristles). Having parapodia and usually head 



and gills. Example : sandworm. 



SUBCLASS II. Oligochceta (few bristles). No parapodia, head, or gills. Ex- 

 ample : earthworm. 



CLASS II. Discophora (bearing suckers). No bristles, two sucking disks present. 

 Example : leech. 



PLATYHELMINTHES (FLATWORMS) 

 Body flattened in dorso-ventral direction. 



CLASS I. Turbellaria. Small, aquatic, mostly not parasitic. Example : planarian 

 worm. 



CLASS II. Trematoda. Usually parasitic worms which have complicated life 

 history. Example : liver fluke of sheep. 



CLASS III. Cestoda. Internal parasites having two hosts. Example : tape- 

 worm. 



NEMATHELMINTHES (ROUNDWORMS) 



Threadlike worms, mostly parasitic. Examples : vinegar eel, Trichina, and hook- 

 worm. 



REFERENCE BOOKS 

 ELEMENTARY 



Sharpe, A Laboratory Manual for the Solution of Problems in Biology. American 



Book Company. 



Davison, Practical Zoology, pages 150-161. American Book Company. 

 Herrick, Textbook in General Zoology, Chap. IX. American Book Company. 

 Jordan, Kellogg, and Heath, Animal Studies, VI. D. Appleton and Company. 

 Ritchie, Primer of Sanitation. World Book Company. 



ADVANCED 



Darwin, Earthworms and Vegetable Mold. D. Appleton and Company. 

 Sedgwick and Wilson, General Biology. Henry Holt and Company. 



