THE HIRUDIN E A OF GEORGIAN BAY 173 



SESSIONAL PAPER No. 39b 



One specimen was obtained by dredging in the French River at a depth of 

 twenty-five or thirty feet. The others were found in small lakes and among the 

 islands. This leech is reported to have been seen feeding upon dead fish, but I have 

 not been able to obtain positive information on this point. 



Family Erpobdellidae. 



The medium size, long, slender form and firm muscular body distinguish 

 this family from others. The presence in the collection of one hundred and eighty 

 specimens in the two species of this family shows that the group is well represented 

 in the Georgian Bay region. 



Genus Erpobdella, Blainville. 



The representatives of this genus are slightly depressed in the posterior region 

 of the body and rounded anteriorly. The five annuli of the complete somite are 

 approximately equal in length. In some specimens the fifth annulus was slightly 

 enlarged and showed signs of division, but dissection revealed the form of sperm 

 duct characteristic of this genus. 



Erpobdella punctata, (Leidy) Moore. 



Nephelis punctata, Leidy (1870) . 



Erpobdella punctata, Moore (1901). 



Of all the leeches in the collection, this species appears to have been the one 

 most commonly taken. Specimens were obtained by dredgings in sandy channels 

 or muddy bays and, along every sheltered pebbly shore either the leech itself or 

 its cocoons were to be found on the lower sides of sticks and stones. The variati ons 

 in color are considerable. Some specimens are light or dark brown with practically 

 no markings while others show a series of dark flecks or dots on either side of the 

 median line. 



While examining these specimens I noticed that a considerable number possess 

 four pairs of eyes, two pairs in somite II and also two pairs in somite IV. The usual 

 number is three pairs (Moore 1901). 



Genus Nephelopsis, Verrill. 



Size large, body much depressed posteriorly. All annuli of complete somites 

 more or less distinctly subdivided. 



Nephelopsis obscura, Verrill. 



.. Seventy-four specimens, large and small, have been thus identified. In size, 

 these vary from 13 to 42mm. in length and from 3 to 5 mm. in breadth. The leech 

 is evidently of the H erpobdellidae, but the greater depression of the body posterior- 

 ly and the greater diameter at that point mark it as distinct from E. punctata. 

 The margin of the body is sharp and may tend upward in the preserved specimen. 



