498 Illinois State Laboratory of Natural History. 



vex, capable of great extension ; no papilla? nor conspicuous 

 markings. 



This widely distributed species is figured by Moquin-Tandon 

 ('46, PL XIIL, Fig. 16-26), and the annulation of the 

 anterior end by Blanchard ('96).* The species is exceedingly 

 abundant everywhere in the shallow waters of rivers, lakes, 

 and ponds, in small streams, pools, and ditches, in fact 

 everywhere where comparatively warm shallow fresh waters 

 are found. It is found clinging to the under sides of stones, 

 and between the ensheathing leaf stalks of aquatic plants, 

 fallen leaves, etc. When disturbed it creeps actively to a 

 place of concealment. The favorite food is small annelids 

 and gastropods, but blood is also taken from injured fish, 

 frogs, etc. The breeding season lasts all through the spring 

 and early summer. 



HEMICLEPSIS \ t EJDOVSKY. 



Hemiclepsis carinata (Yerrill). 



Clepsine papillifera, var. carinata Yerrill ('74). 



Diagnosis, — Somites I and II rather distinctly biannulate ; 

 the single pair of eyes on III ; the widely expanded head 

 pedicellate on a wide pedicle formed by VI ; annulus a 3 of 

 complete somites much larger than a 1 or a 2 and unequally 

 subdivided at the margins ; the dorsum bears three prominent 

 papillated keels; the epididymis and ductus ejaculatorius 

 form a few simple coils in XI and XII. 



General Description. — A medium-sized glossiphonid of 

 striking appearance. It seldom reaches a length of more 

 than one and one half inches when partially extended in the 

 act of creeping. The shape of this species is entirely char- 

 acteristic among known Illinois leeches. In the large size, 

 distinctness, free margin, and pedicellate attachment the head 

 resembles that of the Ichthyobdellida. The body is more slen- 



* By far the best description of this species extant has recently been published by 

 Castle, in Bull. Mus. Conip. Zool., XXXVI. (1900), pp. 21-33. 



