THE HIRUDIN E A OF GEORGIAN BAY 169 



SESSIONAL PAPER No. 39b 



view several micron s posterior to the female genital pore. These tubes appear to 

 bend on themselves, the outer arm ending blindly at about the point where the first 

 pair of gastric caeca appear. The other arm passes backward and appears to con- 

 nect posteriorly with the seminal duct. This blind end may be merely the anterior 

 end of the outer arm of the seminal loop. Also between the genital pores, appears 

 the end of a loop, similar in structure to the oviducts, which passes backward and 

 connects with the oviducts posterior to the female pore. The point of attachment 

 is approximately that of the caecum attached to the oviduct of P. montifera 

 (Moore 1912). 



These specimens were obtained from dredgings in a channel from 3 to 5 fath- 

 oms deep, from under shells, stones and logs in small inlets or in pools. 



Genus Placobdella, Blanchard. 



The collection affords five species belonging to this genus. Form more or less 

 broad and flattened, crop with seven pairs of caeca which are usually more or less 

 branched. As commonly described, the species of this genus possess compact sali- 

 vary glands, but in three of the five species these glands were found to be diffuse. 

 In all the species, however, there was observed a pair of glands opening into the 

 oesophagus similar to those mentioned by Hemingway (1908) as occurring in Placob- 

 della pediculata. These glands are lined with columnar epithelium, whereas the 

 salivary glands are unicellular. Another generic feature is the absence of a seminal 

 loop, but, in one species, viz., P. picta, the seminal duct was observed to form a 

 distinct loop. 



Placobdella parasitica, (Say) Moore. 



Hirudo parasitica, Say (1824) . 



Glossiphonia parasitica, var. plana, Castle (1900). 



Placobdella parasitica, Moore (1901). 



Sixty-five specimens of the collection have been assigned to this species. In 

 size they vary from 8 to 60 mm., in length and from 1 • 5 to 18 mm. in breadth. The 

 color varies from dark or light brown to deep green with a series of yellow markings 

 along the margins and a yellow vitta in the dorsal median line. This vitta may 

 reach the length of the body, expanding at intervals of about three somites or it 

 may be confined to a few somites at the anterior end of the body. Some specimens 

 have an intermediate series of yellow spots. The ventral surface is striped longitu- 

 dinally with light and dark. Dorsally there are three series of more prominent 

 cutaneous papillae and several series of smaller ones. These papillae are always 

 smooth, though inconspicuous in some specimens. The oesophagus is long and 

 looped and at the anterior end of the first loop are the long oesophageal glands. 



The greater number of specimens were found attached to turtles of various 

 kinds, Clemmys guttatus, Aromochelys odoratus, Chelydra serpentina and Chrysemys 

 picta. One was found on a perch, another on a Macrobdella decora and numbers were 

 taken from the lower sides of stones, sticks, etc., in small bays or lakes. 



