THE LEECHES OE MINNESOTA 97 



smallest and very close together or even in actual contact, the others 

 are successively more distant and the third pair is the largest. The 

 first and second are directed forward and outward, the third and 

 fourth backwards and outward. 



The upper lip is very mobile and in preserved examples is almost 

 invariably curled into the cavity of the sucker. The small mouth is 

 far forward in somite II. Genital orifices occur at the positions so 

 frequent in the Glossiphonidcc, the male at XI/XII, the female at 

 XII ■0.2/(13. In one specimen the male bursa is everted in the form 

 of a short conical penis, this being the only species of the family de- 

 scribed in this paper in which such an organ is present. 



Besides the numerous scattered sense organs which roughen the 

 skin there are three pairs of low dome-shaped papillae on each neural 

 annulus except at the anterior end of the body. Apparently these 

 bear the dorso-median, dorso-lateral and dorso-marginal sensillae, the 

 first of which are separated by about one-fourth of the width of the 

 body. 



With the exception of somites X, XI and XII, on which they can- 

 not be detected nephridiopores occur on 02 of every somite from 

 VIII to XXV. Very little is known of the internal anatomy of this 

 species but quite enough to establish its position as a member of the 

 genus. The proboscis is very short and is succeeded immediately by 

 a very short oesophagus and a long stomach which bears nine pairs 

 of branched caeca, two of which are anterior to the reproductive 

 orifices and the last reflected in the usual manner. The muscular 

 system is very peculiar in the wide intervals which exist between the 

 bundles of muscle fibers. 



The color of preserved specimens is a translucent grayish green, 

 the dorsum being rather thickly spotted with cream yellow, the largest 

 spots corresponding with the six series of papillae described above. 

 The annulation presented in figure 12 should not be taken as 

 fully characteristic of the species as it exhibits the somites in the un- 

 developed biannulate or nearly biannulate condition which is observed 

 in the young of all species. With a more pronounced development of 

 the furrows between 01 and 02 it would, however, be diagnostic. In 

 the adult somite I is a distinct but small preocular lobe, II nearly and 

 IV fully biannulate. A very interesting feature, which is found in 

 all of these young and in the few adults which I have studied, is that 

 somite V is shorter and much less elaborate than IV. Somite VI ap- 

 proaches the triannulate type very closely and VII to XXIV inclusive 



