WORMS 169 



snake. It is one of the round worms (related to the " vinegar 

 eel " which is also not an eel) and is parasitic upon beetles, grass- 

 hoppers, and other insects, thus doing considerable good. 



COLLATERAL READING 



Vegetable Mould and Earthworms, Darwin, entire; Life and Her Chil- 

 dren, Buckley, pp. 135-152; Economic Zoology, Osborne, pp. 67-120; 

 Economic Zoology, Kellogg and Doane, pp. 98-105; Elementary Text, Lin- 

 ville and Kelly, pp. 195-235; Practical Zoology, Davison, pp. 150-161: 

 Applied Biology, Bigelow, pp. 340-354; Animal Studies, Jordan, Kellogg 

 and Heath, pp. 59-88; Life in Ponds and Streams, Furneaux, pp. 114-126. 



See also articles under "Worms," "Tapeworm," "Trichina," "Leech" 

 in encyclopedias. 



SUMMARY 



Representatives. 



Earthworm, tapeworm, hairworm, vinegar eel, leech, etc. (not cater- 

 pillars). 



anterior and posterior (define in notes), 

 dorsal and ventral (define in notes). 



External Structure. Shape. 



Segments, count them as far as girdle. 

 Girdle, function. 



Mouth, call attention to pre-oral lobe. Vent. 

 Setae, adaptations. 



1. Number. 



2. Location on sides. 



3. Attached muscles. 



Functions of Setae. 



1. Locomotion, 2. burrowing, 3. food-getting. 

 Reproductive openings on segments 9, 10 and 14, 15. 

 Both sexes in individual. 



Internal Structure. 



Body wall, two muscle layers, use of each. Cuticle. 

 (Lack of skeleton and consequent slow motion.) 

 Digestive system. 



Mouth, manner of food-getting. 



Muscular pharynx, function. 



Crop, stomach, and intestine with special functions. 



(Glands and schemes for increase of digestive area.) 

 Circulatory system. 



Dorsal and ventral vessels. 



Cross tubes in each segment, some pulsate. 



