174 MARINE AND FISHERIES 



5 GEORGE v., A. 1915 



The color is usually light, mottled grey but in some the dorsum is blotched with 

 dark pigment. 



Cocoons similar to those described by Verrill (1872) were found on the lower 

 sides of stones in a pool beyond the reach of the waves. 



Family Ichthyobdellidae. 



This family is represented in the collection by forty-two specimens apparently 

 belonging to at least two species. In the one type there is a slender, rounded body 

 and large explanate suckers; in the other the suckers scarcely exceed the body in 

 diameter while the rounded, slender body tapers toward the anterior end. Both 

 forms possess a protusible proboscis and are parasitic on fishes. 



Genus Piscicola, Blainville. 



For the determination of these forms Verrill's paper (1872) was used and two 

 species have been identified with his genus Ichthyobdella. 



An examination of the external features of the one species would lead one to 

 suppose that it belongs to this genus. The form is slender and rounded, the suckers 

 large and explanate. So far as can be ascertained, fourteen annuli constitute a 

 complete somite. No papillae or sensillae are in evidence. There are two pairs of 

 eyes widely separated on the base of the head. 



Where information is given the specimens obtained at the Biological Station 

 were found clinging to lake trout {Cris^vomer namaycush), but the same form has 

 been found free in the waters of Lake Ontario. 



Piscicola milneri, Verrill. 



Ichthyobdella milneri, Verrill (1872) 



In size this leech varies from 12 to 35 mm. in greatest diameter. The body 

 slender and rounded, tapering toward the anterior end. There are two pairs of eyes 

 plainly visible. The anterior pair are larger and farther apart than the posterior 

 pair. The suckers are two or three times as wide as the body and are deeply cupped 

 and excentrically attached. In the lateral region of the body seventeen pairs of 

 vesicles were observed. The color is deep yellow with a symmetrical pattern in 

 brown. There are four longitudinal yellow bands, dorsal median, lateral and 

 ventral median. The brown color in the form of irregular pigment cells, is laid 

 down in twelve longitudinal lines which are arranged in four groups of three, each 

 group alternating with the yellow bands. 



In each group of brown lines the uppermost line is more or less broken, show- 

 ing a tendency to a series of heavy brown metameric bars. On the posterior sucker 

 twelve dark brown eye-spots were observed. Verrill speaks of a tinge of green, 

 but this was not observed in any of the specimens in the collection. The absence 

 of this color, however, may be due to the effect of the preserving fluids. 



These specimens were taken on lake trout (Cristivomer namaycush). 



