THE LEECHES OF MINNESOTA 121 



Genus Erpobdella Blainville. 



Size moderate ; posterior region not greatly depressed. Sperm 

 duct forming a long loop (reaching to ganglion XI) anterior to atrium, 

 which is provided with a pair of simply curved horns. None of the five 

 annuli of complete segments distinctly enlarged and subdivided. 



Erpobdella punctata (Leidy) Moore. 



(Plate IV. fig. 39) 



Nephelis punctata Leidy (1870) 

 Nephelis lateralis Bristol (1898) in part. 

 Erpobdella punctata Moore (1901) 



Description — The form is elongated with the sides nearly parallel, 

 tapering anteriorly to the clitellum but very little at the posterior end. 

 Anteriorly it becomes almost circular in section and posteriorly, al- 

 though margins are sharp and prominent, is little depressed and 

 widened. The size is large for the family, reaching a length of about 

 five inches. The body is very firm, hard and muscular. 



The oral sucker is very small, being little more than a short lip 

 overhanging the nearly terminal mouth. Normally there are three 

 pairs of eyes, the first decidedly the largest and situated close together 

 on somite II and directed forward; the others more widely separated 

 on the sides of IV and looking somewhat backward. The clitellum 

 is frequently seen in full development, in which condition it is a wide, 

 thick complete girdle covering the fifteen annuli from X bj to XIII a2 

 inclusive. The male pore is a rather conspicuous opening at XII 

 b2,'a2, the female a much smaller one at XII bfj/b6 or two annuli 

 farther caudad. 



Somites I. II and III are uniannulate ; IV and V are biannulate , 

 VI is triannulate, VII quaclriannulate ; and VIII to XXIV inclusive, 

 or seventeen somites, are quinquiannulate. At the posterior end somite 

 XXV is quadriannulate, though the last annulus (o?) may be more 

 or less distinctly subdivided on the dorsum; XXVI is either biannulate 

 or triannulate and XXVII is usually uniannulate. 



In the complete somites the annuli are of approximately equal 

 length and b6 is not obviously enlarged or more completely subdivided 

 than the others. Numerous small cutaneous papillae bearing sense 

 organs appear arranged in an irregular transverse row on each an- 

 nulus. They are largest dorsally and on the neural annulus. The 

 annuli of the simpler somites frequently exhibit two such rows, indicat- 

 ing their composite character. 



