THE LEECHES OF MINNESOTA 127 



Whatever pigment may have been present has faded out com- 

 pletely in the preserved material. Nothing is known concerning the 

 habits of this species. 



Dina fervida (Verrill) Moore. 



(Plate VI, fig. 42) 



Nephelis fervida Verrill (1874). 

 Dina fervida Moore (1901) 



Description — The length of this species is not known to exceed 

 three inches and more often reaches but two. The body is depressed 

 posteriorly but rounded anteriorly. The mouth is of relatively large 

 size and the lips broadly rounded. More characteristic is the large 

 size of the caudal sucker which has a greater expanse than in most 

 small nephelids, the anterior margin being more widely free and reach- 

 ing as far forward as XXV a2. If one may judge from the prepara- 

 tions the body is not of particularly firm consistency ; certain it is that 

 the muscular system is less well developed than in the hard species. 

 The usual thick prominent clitellum reaches from X b$ to XIII a2 

 covering fifteen annuli. The external genital orifices are separated 

 by two annuli, the male being situated at XII b2la2, the female at 

 XII bfj/b6. Three pairs of eyes are more usual than four. They re- 

 semble those of E. punctata except that the pigment cups of the first 

 pair lie chiefly within somite III. 



There is little of diagnostic value in the annulation. Some 

 features of the sense organs are peculiar but have no considerable 

 value in defining species. The last annulus (b6) of each somite is 

 much longer and more fully and constantly subdivided than any of 

 the others, as in other members of the genus. 



The species is very readily distinguished from D. parva by the 

 character of the reproductive organs. The testes occupy the lateral 

 portions of somites XVIII to XXIV, and average in the one in- 

 dividual in which they were all counted thirty-two on each side of 

 a somite. The several regions of the sperm ducts exhibit no peculiari- 

 ties until the atrium is reached. Here the entire absence of a pre- 

 atrial loop is noted, the ejaculatory canals stopping abruptly at the 

 apices of the atrial cornua into which they enter. When the copu- 

 latory organ is fully retracted the ducti form no loop whatever anterior 

 to the atrium but when, in protrusion, the cornua are drawn somewhat 

 caudad, they sweep somewhat anterior to it in a broad curve. The 

 atrium itself is characterized by the relatively large size and quite un- 



