[24 THE LEECHES OI- MINNESOTA 



size ; the anterior two pairs are situated nearly side by side in somite 

 II, or the more lateral pair in a slightly more caudal position on the 

 furrow II/III. Both are directed forward and slightly lateral. The 

 remaining two pairs are situated farther back but similarly close to- 

 gether on the sides of the oral annulus IV. Usually they are on the 

 posterior part of the larger annulus but their pigment cups may lie be- 

 neath the furrow ai/aj. Both are directed caudad and laterad. 



Fifteen annuli, X b$ to XIII a2 inclusive, are occupied by the 

 prominent clitellum. The external genital orifices are separated by 

 two annuli situated as in E. punctata at the furrows XII bi/aj and 

 XII bs/b6 respectively. In individuals which are in active sexual 

 condition, the male orifice is a conspicuous opening more or less ele- 

 vated on pouted lips marked by radiating furrows. Occasionally the 

 genital bursa is everted as an elliptical disc with a central platform- 

 like elevation perforated by a single median pore or a pair of pores, de- 

 pendent on the more or less complete protrusion of the organ. In small 

 individuals and those not sexually active the male pore is minute, as 

 the female invariably is. 



The anus. is a rather large transverse slit with wrinkled margins 

 situated in XXVI and succeeded by several rather ill defined annuli 

 belonging to XXVII. The caudal sucker is a thin, flat, expansive and 

 largely exposed disc. Its dorsal surface is marked as in E. punctata 

 by six or eight radiating ridges. 



In one respect the reproductive organs are very characteristic. 

 While in general resembling E. punctata the atrial cornua arc larger 

 and coiled in a complete spiral turn, which is invariably present in a 

 large number of individuals of all sizes and conditions which have 

 been dissected. The pre-atrial loops reach to ganglion XI. 



The ground color is generally gray, clay color or brownish, the lat- 

 ter occurring most frequently on plain unspotted examples. By far the 

 greater number of specimens are thickly spotted over the entire dorsal 

 surface with black. These blotches are not coarse and heavy as in 

 Hccmopis marmoratis to which the species exhibits some resemblance 

 in color, but are finely branched and ramifying, with frequently anas- 

 tomosed terminal branches, thus affecting a more or less evident and 

 continuous network. Sometimes the black spots are quite few and 

 remote, again they become so predominant that the ground color is 

 very largely obliterated and the dorsum presents a generally slate 

 black color spotted more or less remotely with the lighter ground. 



In any case, whether the spots be few or many, there is no evident 



