THE LEECHES OF MINNESOTA 113 



as is well known to be the habit of the Limnatis so common in some 

 of the countries bordering on the Mediterranean. 



Haemopis lateralis (Say) Moore. 



(Plate III, fig. 23) 



Hirudo lateralis Say (1824). 



? Macrobdclla valdiviana et gigas Philippi (1872) • 



Semicolex tcrrestris Forbes (1890) 



Hccmopis lateralis Moore (1901) 



Description — Although there are some minor differences I am 

 unable to separate the aquatic leech originally described by Say from 

 specimens procured in Minnesota from the interesting terrestrial form 

 which Forbes has described and which was found by him in consider- 

 able numbers in garden soil in Illinois. So far only the aquatic variety 

 has been found in Minnesota and was represented in the Survey 

 collections by two living examples which unfortunately escaped from 

 me and were lost. 



Compared with the terrestrial variety, of which even Prof. Forbes' 

 contracted alcoholic specimens reach a length of eight inches, a large 

 number of the aquatic form, chiefly from Ohio and Maryland, average 

 much smaller, about five inches long and one-half inch wide being the 

 usual size. This species is much more slender than H. marmoratis 

 and the greatest width lies farther caudad. The body is rather more 

 muscular and as a consequence firmer, but during life exhibits the 

 same variety of shapes and postures. 



The mouth is somewhat smaller and the oral sucker narrower 

 than is II. marmoratis, while a further slight distinction is found in 

 the better developed longitudinal grooves beneath the lips of this 

 species. The eyes have the same number and position as in the 

 species last described. 



In the few cases in which a clitellum has been observed it differs 

 in no respect from II. marmoratis. Although not differing in any way 

 from the typical arrangement in the family, the seventeen pairs of 

 nephridropores on the posterior margin of 02 of somites VIII to 

 XXIV inclusive are unusually distinct and lie just behind a sort of 

 slight spout-like projection. The posterior sucker is noticeably small. 



Throughout the entire length of the body the annulation is very 

 distinct, and at the margins most of the annuli are rather sharply 

 angulated. In most respects the somites are constituted just as in 



