2o6 AQUATIC MICROSCOPY FOR BEGINNERS. 



collecting-bottle after it has been standing for some 

 time. Usually they bury themselves in the mud, with 

 the posterior part of the body and the expanded fun- 

 nel-like region protruded from small mud-chimneys of 

 their own formation. The body may measure half an 

 inch or more in length. 



6. Aul6phorus (Fig. 151). 



The posterior extremity is not wider than the width- 

 of the body, and the two finger-like appendages may 

 be straight or slightly curved. They are blunt, and 

 covered with short stiff hairs. 



The worm usually builds a tubular 

 sheath of various fragments and floating 

 particles, in which it lives, but to the 

 walls of which it is not adherent, as it 

 ^'ferior'extrem' frequently doubles on itself, glides 

 phorus.""*^"'*' through the tube, and thus reverses its 

 position. It moves by jerks, -'alter- 

 nately extending the fore part of the body and pro- 

 jecting the podal fascicles forward, and hooking into 

 the surface on which it is creeping, and then contract- 

 ing the fore part of the body and dragging along the 

 back part enclosed within the tube."* It often helps 

 itself along by clinging to the slide by its protruded 

 throat or pharynx. 



The podal spines vary from five to nine in each 

 cluster. The fascicles of bristles are each accom- 

 panied by from one to three rudimentary spines, which 

 are nearly straight, and end in a broadened, spade- 

 Jike expansion. The blood is' red. 



*Dr. Joseph Leidy, in the American Naturalist, June, 1880. 



