OF ARTS AND SCIENCES. . 89 



being taken not to crush it. This may be clone by arranging two 

 pieces of wire, of the diameter of the worm, so that their ends project 

 between the edges of the ccver-glasses. The ghiss slide may be laid 

 for the purpose on a piece of wood, into which the other ends of the 

 wires are fastened. After being straightened in this way, they may be 

 rendered rigid enough for handling by placing on them while still 

 between the cover-glasses a few drops of 70 per cent alcohol, in which 

 they should remain for a minute or two. They are most readily 

 handled by means of a pipette. 



General Description and Habits. 



AuIopJiorus vagus was named and described by Leidy in the Ameri- 

 can Naturalist for June, 1880, as follows: — ''Our species I propose 

 to name Aulop/torus vagus. Body cylindrical, compressed, transparent, 

 with red blood and yellowish-brown intestine. Single individuals of 

 the third of an inch or more in length, composed of from 24 to 35 

 rings. Head ovoid, extending as a conical upper lip, very mobile and 

 changeable in form, oljtuse or sub-acute and minutely hirsute. Eye- 

 less. Caudal ring contracted, and furnished with a pair of long, diver- 

 gent, digit-like appendages, which are straight or slightly incurved, 

 blunt, and minutely hirsute. Anal aperture surrounded by a rosette 

 of half a dozen piominent, blunt, conical papilliB. The four rings suc- 

 ceedins; the head furnished on each side with fascicles of seven to nine 

 podal stylets ; the succeeding rings, except the last, with fascicles of 

 5 to 6 podal stylets, which are shorter than the former. Podal stylets 

 sigmoid with a median shoulder and ending in a furcate hook. The 

 same posterior rings furnished dorsodaterally with fascicles consisting 

 each of usually a single moderately long bristle and a single nearly 

 straight stylet ending in a spade-like expansion. Pharynx capacious, 

 going into the fifth ring, and narrowing into an oesophagus, which ends 

 in the intestine within the ninth rin<T. Generative organs unobserved. 

 Worm of 3 to 5 lines in length, or more, according to its degree of 

 extension. Livin<j in a tube of its own construction, which it dra"s 

 about with it. The tube is composed of a transparent cement or 

 basis, incorporated with various materials, such as vegetal particles, 

 sand, dirt, diatoms, spongilla spicules, etc. In creeping about among 

 aquatic plants, Lemna and Wolffia, the worm stretches in such a man- 

 ner that one third of the body extends from the fore jiart of the tube, 

 while the forked caudal extremity remains projected from the back 

 end. The worm moves in jerks, alternately extending the fore part 

 of the body and projecting the podal fascicles forward and hooking into 



