Transactions of The Royal Society of Canada 



SECTION IV 

 Series III DECEMBER 1915 Vol. IX 



Trematodes from Marine and Fresh-Water Fishes, including one 

 Species of Ecto parasitic Tiirhellarian. 



By A. R. Cooper, M.A. 



Presented by Dr. B. A. Bensley. 



(Read May Meeting, 1915.) 



The following paper is a semi-descriptive list of flat-worms, with 

 one exception trematodes, taken from marine and fresh-water fishes 

 at the Marine Biological Station and Lake Station on Georgian 

 Bay, respectively. Unless otherwise stated the hosts were actually 

 procured in the immediate vicinity of St. Andrews, N.B., and Go- 

 Home, Ont., in the former case from Passamaquoddy Bay. Twenty- 

 nine species belonging to 24 genera are reported from 29 species in 27 

 genera of fishes, and of these one is a Triclad Turbellarian while five 

 are ectoparasitic or monogenetic trematodes. Ten species (Nos. 3, 7, 

 10, 11, 13, 14, 16, 18, 20, 25) are to my knowledge here reported for 

 the first time from Canada. 



Very early stages in the development of several species were 

 found encysted in what are in all probability at least the second inter- 

 mediate hosts. They seem to point to a very simple life-history in 

 each case, although nothing is given with regard to the period between 

 the eggs and such very young stages. In several instances eggs — 

 containing living miracidia in the case of Allocreadium commune 

 (Olss.) from may-fly nymphs of the genus Blasturus — were found in 

 the uteri of mature .encysted individuals or extruded into the cavity 

 of the cyst, which facts point to self-fertilization or parthenogenesis, 

 since each cyst contained only one worm. A thorough study of the 

 fertilization processes of any species falling into this category would 

 doubtless bring to light some very interesting facts. 



A few explanatory figures are given for the assistance of future 

 workers in this field, while an apparently long list of references is 

 supplied. The latter, however, contains in most cases only those 

 works giving adequate descriptions of the species in question. The 

 numbers in bold-faced type throughout the text refer to this list. 



Sec. IV, 1915—12 



