44 LEIDY'S DESCRIPTIONS OF AMERICAN WORMS. 



short or rudimentary. Upper lip triangular, studded with short stiff hairs. Mouth 

 round. Eyes consisting of a pigment spot on each side of the oral segment. Anal 

 segment rounded, furnished with short, stiff hairs. (Esophageal division of the 

 intestine passing to the sixth articulation, where it terminates in the distinct, dilated, 

 fusiform, commencement of the ventricular intestine. Cavity of the body, between 

 the viscera, filled with free, floating, granular corpuscles. 



In a specimen elongated to seven lines there are usually four divisions, of which 

 there are about 3 lines to the anterior division, | of a line to the second, 1| to the 

 third, and 2 lines to the last. Breadth about l-80th in. 



Habitation and Remarlis. — This worm is found feeding among confervse on the soft 

 muddy borders of clear rivulets, in the neighborhood of Philadelphia. I never found 

 an individual which was not more or less in a state of division, in fact before the 

 last segment is ready to separate from the parent, there are a number of narrow 

 segments, with rudimentary podal spines and setse, already formed at its posterior 

 extremity, which are to become a new and distinct individual. In the average of 

 several specimens of four lines of length when shortened, seven lines when 

 lengthened, of four divisions, there were sixteen setigerous articulations to the 

 anterior division, the setse being l-75th in. long ; eight to the second, with the setse 

 comparatively very short, being yet quite rudimentary, and measuring from the 

 l-500th to the l-200th in. long : thirteen to the third with the setse the j-lOOth in. 

 long; and eighteen to the last, excepting those which are rudimentary of a new 

 division of the animal posteriorly, with setse as long as those of the first, and 

 frequently even longer. 



Pristina, Elirenherg. (Symbolse Physicse.) Labio superiore in proboscidem 

 stiliformem longissime producto et angustato, molli, (barbate).* 



3. Pristina longiseta,! EJirenh. Fig. 3. — Body whitish, linear, composed of 

 sixteen elongated articulations, all, with the exception of the first, furnished upon each 

 side inferiorly with a set of eight, retractile, uncinated, podal spines, every one also 

 supplied upon each side with three very long setse : those of the second articulation 

 twice the length of the others : those of the last two articulations often two or only 

 one on each side, and comparatively short Upper lip elongated into a long bent, 

 proboscidiform process, which is soft, and bordered and studded with short, distant, 

 stiff hairs. Eyes none. Mouth triangular. Alimentary canal consisting of a narrow 



* Further in the Diet. Univ. Hist. Nat. t. 8, p. 5G8. " Pristina, Eliren. Des soies laterales assez longues ; des 

 crochets ventraux ; ocelles nuls ; la levre superieure prolongee en une trompe filiforme garnie de soies." 



•j- 1 regard this as the P. Jongiseia of Ehrenberg, because in a note to the characters of the genus Pristina, in 

 the Sombolte Physics, he describes a species, which as far as the description goes, corresponds with it. " Pristina 

 longiseta internoscitur ; setis ternis, fasciculorum pari secundo longissime, proboscidem superante, uncinis 

 septinis aut octonis." 



