48 LEIDY'S DESCRIPTIONS OF AMERICAN WORMS. 



I can gather from the account of this worm in Wiegmann's report on the Annulata 

 in the Archiv fur Naturgeschichte, year 1838, volume 2, page 344, and the 

 description of Hoffmeister in the same work, year 1843, volume 1, p. 193, the above 

 characterized worm is probably the same. 



7. Enchytraeus socialis. Figs. 13 to 15. — Body opalescent white, translucent, 

 permitting the generative organs and the course of the intestine to be seen through 

 the tegument, anteriorly moderately attenuated and terminating by a triangular upper 

 lip, posteriorly cylindrical. Anal segment cylindrical, truncated. Articulations not 

 over fifty-two, twelve anterior to the girdle, which latter is well marked. Podal 

 spines five to seven in each fasciculus, simple. Mouth triangular, oesophagus passing 

 to the eighth articulation, intestine simple, or frequently presenting the appearance 

 of an oblate spheroidal gizzard in the eighth articulation. Generative apparatus 

 perfect. 



Length 5 to 10 lines, breadth at girdle l-56th in. More common than the other 

 species, usually found in considerable numbers under the bark of damp decaying 

 stumps of trees, or under the bark of decaying portions of living trees quite near the 

 ground, in all the forests of eastern Pennsylvania. 



Remarhs. — This species of Enchjtraeiis although quite as long as the first, has a 

 smaller number of articulations. The podal spines in each fasciculus in this species 

 are more than are called for in the genus of Henle, although they have the same 

 form ; simple, divergent, and with a short transverse manubrium at the origin for 

 muscular attachment. They are usually in fasciculi of six, the central ones shorter 

 than the outer ; anterior to the girdle, many of the fasciculi have seven spines, and at 

 the posterior part of the body they have but five. The spines average the 

 l-333d of an inch long. The oesophagus is narrow and delicate to the eighth 

 articulation, where it joins either the dilated commencement of the ventricular 

 intestine, or an oblate spheroidal contraction of the same very much like a gizzard in 

 appearance. At first I thought the animal possessed a true muscular gizzard, but in 

 more than half the number of individuals examined, there was nothing existing 

 but a dilatation of the ventricular intestine with a thickening of the parietes, 

 extending from within the eighth articulation to the commencement of the girdle; at 

 other times there was an appearance of a distinct gizzard, and a dilated thickened 

 appearance after it to the girdle, as represented in Plate 2, and in the fewest 

 number of instances the oblate spheroidal contraction alone existed ; but in all 

 cases that portion of the intestine extending from within the eighth articulation to 

 the girdle is strongly muscular, and may subserve the purpose of a gizzard. Within 

 the girdle the intestine is narrow, posterior to it, it is moderately tortuous, irregular, 

 and capacious. 



