226 [June, 



movements, and appears to have the power of fixing itself by the end of the tail 

 to surrounding objects. 



7. Angctillula fossularis. 5 Body cylindrical, anteriorly narrowed, trun- 

 cated. Mouth round, surrounded by a prominent circular lip; buccal apparatus 

 none ; pharynx short ; oesophagus long, clavate, or fusiform, slightly tortuous ; in- 

 testine cylindrical, brown in color ; rectum distinct, cylindrical, colorless. Tail 

 acute. Ovary double. Generative aperture anterior to the middle. 



Length 2 to 2i lines ; breadth l-250th in. Tail l-50th in. long from anus. 

 CEsophagus l-28th in. long ; l-1333d in. broad at commencement ; l-400th m. at 

 termination. Intestine l-475th in. broad. Rectum l-75th in. long. 



Hab. Stagnant ponds and rain-puddles in the suburbs of Philadelphia. 



AcESTUs, Leidy. 



Body vermiform. Podal spines in 4 rows ; anteriorly 3 to 5 in each fasciculus, 

 posteriorly in pairs ; long sigmoid, bifurcated at extremity. Upper lip conoidal, 

 inarticulate. Annuli under 100. Blood red. Eyes, girdle and muscular 

 stomach none. 



8. AcESTUs SPIRALIS, n. s. Body cylindrical, posteriorly attenuated, obtusely 

 terminated; color reddish; integument thick. Annuli 80 ; anterior five with 5 

 podal spines in each fasciculus, afterwards 3 in each, and posteriorly in pairs; 

 furnished with a shoulder, and a bifurcate unguiform extremity. CEsophagus 

 passing the sixth annulus. Intestine simple, cylindrical, capacious. Blood 

 vessels large, tortuous, without distinct coeca, filled with red blood. 



Length 1 inch; breadth anteriorly l-12th line; at middle 1-lOth line; posteri- 

 orly l-16th line. Lip l-280th in. long from mouth. Podal spines l-400th in. 

 long. 



Kah. In the soft mud at the bottom of stagnant ditches and ponds in the 

 neighborhood of Philadelphia. 



Remark. When drawn out of its concealment in the mud, it rolls the posterior 

 J of the body into a spiral. 



9. AcESTus HYALiNus, M. s. Body cylindrical, posteriorly obtuse, hyaline. 

 Annuli 24 to 34. Podal spines anteriorly 3 to 4 in each fasciculus, posteriorly 

 in pairs, swollen slightly one-third their length from the extremity, which is 

 unguiform and bifurcated. Blood faintly red. 



Length li to 3 lines; breadth anteriorly l-333d in. ; middle l-2S0th in. ; pos- 

 teriorly l-400th in. Lip l-500th in. long. Podal spines l-550thin. long. 



Hah. Found with the preceding, its anterior half buried in the mud and the 

 tail rapidly vibrating like Saenuris or Strephuris. 



Dero, Oken. 



Body vermiform. Podal spines in two rows. Lateral setas. Caudal append- 

 ages. Blood reddish. Proboscis and eyes none. 



10. Dero limosa, n. s. Body cylindroid, faintly reddish, translucent. 8, 16, 

 26 to 34 setigerous annulations when the body is in from 1 to 4 divisions. Five 

 anterior annuli without setae. Two rows of podal spines ; 5 to 6 in each fascicu- 

 lus anteriorly ; 3 to 4 posteriorly; long sigmoid, bifurcate at extremity. Setas 

 single, in one row upon each side. Caudal annulation, expanded, truncated. 



