i if, THE LEECHES OF MINNESOTA 



ment. The sensillse, nephridiopores and anus present no distinctive 

 features. None of the specimens examined has the clitellum de- 

 veloped. 



The annulation is essentially like that of //. g rand is but a few 

 differences occur, which may disappear when a larger series of speci- 

 mens comes to he compared. The furrows are well marked hut pre- 

 sent little of that zigzag character and secondary wrinkling which is so- 

 conspicuous in the larger species. This difference is very marked in 

 specimens of the two species of equal size and preserved together, so 

 that it may prove not to be accidental. The furrow V ai/a2 is quite 

 incipient and the annuli ATI a? and YIII ai are relatively much 

 smaller and very much less distinctly subdivided than in H. grandis. 



The mouth is very large and the ventral surface of the lip shows 

 no trace of longitudinal sulci. Jaws are absent and the capacious 

 pharynx bears twelve very low longitudinal folds. The remainder of 

 the alimentary canal appears to differ in no way from that of H. 

 grandis. 



The external genital orifices are constantly in the middle of annuli 



XI b6 and XII b6 respectively, while in H. grandis the male pore is 

 almost invariably at XI b$/b6 and the female in the anterior part of 



XII b6. The penis is filiform and may protrude to a length of two and 

 one-half times the width of the body at the male orifice. It is in the 

 structure of the internal reproductive organs that the most evident 

 differences between this species and H. grandis are found. In fact 

 the resemblance is much closer to H. niarnioratis in respect to these 

 organs. The atrium extends caudad far beyond the vagina to the 

 neighborhood of ganglion XVI where the usual sharp bend occurs. 

 The short limb is about one-half as long as the long one. Relatively 

 small sperm sacs, which are not more than one-fourth or one-fiftli of 

 the length of the atrium, lie far forward in the region of the male 

 orifice. The coils of the epididymes lie chiefly by the side of the sperm 

 sacs and not heaped up at their caudal end as in //. grandis. Unlike 

 any other species of the genus described in this paper the vagina is 

 very much shorter than the atrium, reaching only to the caudal end 

 of the somite XIV. The common oviduct lies on the dorsal side of 

 the vagina ; the albumen gland is large and nearly spherical and the 

 ovaries are just in advance of the female pore. 



The color is a remarkably uniform leaden or slaty gray, usually 

 purer and sometimes darker below, and often showing a slight olive 

 or yellowish tinge above. Along the entire lateral margins from the 



