THE HIRUDIN E A OF GEORGIAN BAY 167 



SESSIONAL PAPER No. 39b 



Glossiphonia stagnalis, (Linn.) Johnston. 



Hirudo bioculata, Bergmann (1757). 

 Hirudo stagnalis, Linnaeus (1758). 

 Clepsine modesta, Verrill (1872). 

 Helobdella stagnalis, Blanchard (1896). 



In the collection there are fifty-seven adult specimens, together with a number 

 of young which appear to belong to this species. Size small, usually not exceeding 

 an inch in length when extended. The crop, when empty, shows one pair of long 

 posterior caeca, which lie alongside the stomach. When the crop is full, five or 

 six pairs of caeca may be visible, but usually only three or four pairs can be seen. 

 At the twelfth annulus there is a small brown chitinous plate on the dorsum, which 

 marks the position of the nuchal gland; this plate is usually visible to the naked 

 eye and furnishes a means of distinguishing the species. The simple eyes in the 

 fourth somite of this leech correspond to those of G. nepheloidea. The color is 

 generally white to semi-transparent, but some specimens are flecked with grey. 



In specimens collected in the vicinity of Toronto last autumn a pair of con- 

 spicuous white spots, close to the dorsal median line were observed. These, on 

 closer examination, proved to be the atria showing through the transparent body- 

 wall. These spots were not observed in the Georgian Bay specimens, but since 

 they become less conspicuous after preservation, it is probable that their absence 

 is due to the effects of the preserving fluids, or possibly there is a difference in respect 

 of the season of the year. 



In one instance a leech of this species was found attached to a tadpole in a 

 pool where tadpoles were numerous. In other instances, specimens were taken 

 in dredgings from swampy bays or from under stones or again on aquatic plants. 



Glossiphonia fusca, Castle. 



Clepsine papillifera, var. lineata, Verrill (1874). 

 [Not Hirudo lineata, O. F. Miiller (1874)]. 

 Glossiphonia lineata, Moore (1898). 

 Glossiphonia fusca, Castle (1900). 



Twenty-one specimens have been identified as belonging to this species. 

 Size from 5 to 13 mm. in length and from 1*5 to 3*5 mm. in breadth; crop of five 

 or six pairs of caeca, not greatly branched. Shape very similar to that of G. stag- 

 nalis but not so capable of extension. The color varies from yellowish grey to 

 almost white. On the dorsal surface there are usually three to five series of rather 

 prominent papillae. Along the line of the papillae there is a more or less complete 

 longitudinal white band and the papillae are frequently tipped with black. The 

 simple pair of eyes are located on the fourth annulus or in the furrow between the 

 third and fourth. Several specimens were taken from the lower sides of sticks. 



