NORTH AMERICAN FRESH-WATER LEECHES. 685 



anteriorly there is a pale yellowish green median line ; a slight distance 

 from the middle there is, on each side, a narrow black line extending 

 the whole length, and between these and the margins there are other 

 faint longitudinal lines. Along each margin, there is a row of about 

 six sulphur yellow spots, and a few smaller raised yellow spots are scat- 

 tered over the back, the anterior ones often becoming greenish. Lower 

 surface pale green, specked with brown, and with a light median and 

 two black longitudinal lines, corresponding to those above. 



Var. b. — Two anterior ocelli nearer together than the others. Body 

 deep brown, in i>reserved specimens, with six or more irregular rows 

 of yellow spots on slightly raised papillse. 



West River, with the two preceding — A. E. Yerrill ; Lake Ontario — 

 Nicholson; northwest-boundary survey — Dr. E. Coues, (var. aand&.) 



This is a very active species. It adheres firmly by means of its pos- 

 terior sucker, but when much disturbed quickly rolls itself into a ball. 

 One of the specimens, taken June 6, carried about a dozen slender 

 young ones, of a pale pink-color. 



In addition to the preceding species, Clepsine oniscus Diesing, (Blain- 

 ville, sp.,) and Clepsine swampina Dies. (Bosc, sp.,) have been indicated 

 from North America. The first has not been described sufficiently to 

 be recognized, all the characters mentioned applyiu g equally to nearly 

 every species of the genus. 



Clepsine sivampina Diesing is thus described : " Body subellipti- 

 cal, depressed, anteriorly narrowed, above transversly sulcated, below 

 plumbeous. Ocelli six, two closely approximate. Acetabulum orbicular. 

 Length, 6-7 lines ; width, 3 lines." 



Carolina, upon the surface of tortoises and frogs — Bosc. 



Section D.— Ocelli 8. 

 Subsection a. — Back smooth. 



Clepsine occidentalis Yerrill, sp. nov. 



Body rather stout; in contraction thick and convex; about 0.75 of 

 an inch long, and 0.30 broad 5 tapering to both ends. Ocelli eight : those 

 of the second and third pairs largest; those of the third farthest apart; 

 those of the fourth small and near together. Dorsal surface smooth, 

 with faint indications of small, low papillae anteriorly. Acetabulum 

 small. Color, in alcohol, yellowish brown, with fine transverse lines of 

 darker. 



San Luis Valley, Colorado — H. W. Henshaw, Wheeler's expedition, 

 1873. 



Cystobranchus vividus Yerrill. 



Op. cit., vol. iii, p. 126, fig. 1, 1872. 

 Body elongated, somewhat depressed, tapering both ways, but most 

 so anteriorly. Surface smoothish, but with minute, hemispherical hya- 



