THE LEECHES OF MINNESOTA 107 



The. body is depressed throughout, more so than in any native species 

 of the family and the margins are sharp. During life, however, the 

 body is very soft and assumes a great variety of attitudes and shapes. 



The oral sucker is a powerful organ provided with a rather wide 

 rnsegmented and very mobile border which very materially increases 

 its extent. Anteriorly a distinct median emargination corresponds 

 with a deep ventral sulcus which divides the upper lip and is flanked 

 by a pair of somewhat shallower sulci. The upper lip can be folded 

 into the buccal chamber and almost concealed by the lateral lobes 

 which close beneath it. As usual in the family there are five pairs 

 of eyes, larger in this species than in the species of Hcvmopis. Their 

 arrangement is sufficiently indicated in the figure. The posterior 

 sucker is large, broadly attached and circular. 



When fully developed the clitellum is firm and thick and extends 

 over eighteen annuli, from X b-, to XIV b2, but it is seldom so well 

 marked nor so extensive. In the ordinary condition the male pore 

 appears as an opening of considerable size in the furrow XI/XII. 

 into which the surrounding regosities converge. When these inflected 

 parts are everted they form a more or less prominent conical penis 

 which reaches a length of about three millimeters when fully pro- 

 truded. In this condition it is supported almost entirely on annulus 



XII bi which has greatly encroached on the preceeding annulus in 

 the middle region. The female orifice is a small opening with rugous 

 margins situated at XII/XIII or XIII bi. 



Very characteristic of the genus are the copulatory glands, which 

 form conspicuous masses occupying a large part of the middle region 

 of the floor of somites XIII and XIV. Their external openings are 

 four in number, arranged at the four angles of a nearly square figure, 

 the first pair opening in the furrow XIII/XIV and the second in the 

 furrow line XIV bi/bp. Surrounding each of the pores is a slightly 

 tumid region extending over the contiguous halves of the two annuli 

 between which the pore lies. When fully developed the four tumo- 

 sities are separated only by shallow furrows and together form a con- 

 spicuous rugous quadrate area extending over the posterior half of 



XIII b6, the anterior half of XIV b? and all of the intervening an- 

 nulus. Longitudinal and transverse diametral furrows divide it into 

 quarters. 



The surface of the body of this species is quite smooth and free 

 from papillae, although more or less roughened in some preparations 

 by the scattered sense organs. Nephridiopores and sensillae have the 



