LEIDY'S DESCRIPTIONS OF AMERICAN WORMS. 45 



tortuous oesophagus passing as far back as the commencement of the seventh 

 articulation, where it terminates in a cordiform expansion of the ventricular intestine ; 

 the latter moderately tortuous and capacious. Anal articulation cylindric, obtusely 

 rounded, and studded with short, stiff hairs. Generative apparatus occupying the 

 third to the sixth articulation. 



Length 1 line ; greatest breadth l-150th in. Length of oral articulation with 

 labial prolongation l-83d in. Setae of second articulation l-33d in. long ; the others 

 averaging l-75th in. long. 



Habitation and Remarks. — Found with the preceding. This animal is very active 

 in its movements; it is abundant in its peculiar localities, and is usually found in the 

 state of multiplication by division. When the posterior division is almost perfected, 

 it is nearly as long and has as many articulations as the anterior, and from the oral 

 articulation the labial prolongation appears as a rounded antero-lateral projection, 

 (fig. 3, a.) 



In a wineglass of water containing some fine dirt and algse, in which were preserved 

 for several months a considerable number of Pristina longiseta, I frequently noticed, 

 in the dirt, minute eggs, which I supposed to belong to this animal. Ihey were 

 white, oval, always isolated, measured 1-1 33d in. long by 1 -130th broad, and were 

 surrounded by a tough mucoid substance. 



Strephuris,* n. g. — Podal spines alternating with setse, in two rows. Upper lip 

 moderately projecting. Girdle well marked. Number of articulations not over 

 seventy. No muscular stomach. Blood bright red. 



4. Strephuris agilis. Figs. 4 to 7. — Body soft, filiform, acute anteriorly, 

 increasing in thickness to the girdle, which is placed posterior to the ninth articulation, 

 gradually decreasing in breadth posteriorly. Tegument faintly reddish, transparent, 

 through which is seen the large red dorsal and ventral vessel, with the white or 

 brown, tortuous intestine. Articulations pretty uniformly seventy in number, 

 supplied on each side inferiorly with a fasciculus of retractile podal spines, 

 alternating with setse three times the length of the former. Fasciculi anterior to the 

 girdle consisting of four podal spines and three setaB ; posterior, of two or three podal 

 spines and one or two setse. Podal spines elongated sigmoid, bifid at the free 

 extremity, l-229th to l-200th in. long. Setse simple, stiff, 1-1 14th to l-55th in. long. 

 Upper lip triangular, furnished with very short straight hairs. Mouth triangular. 

 Qiisophageal division of the intestine passing as far as the sixth articulation. Oral 

 segment l-57th in. long. Anal articulation cylindrical, furnished with short, stiff 

 hairs, l-178th in broad. Generative apparatus complete. 



* Sfpf^w torqueo ; et oupa. ■ 



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