146 THE CANADIAN NATURALIST. [June 



wliich extends unclcrneatli tlie valves, along the raphe to the 

 apices, and in which a movement is sometimes seen, is in con- 

 nection, by means of excessively minute pores in the raphe, with 

 a similar, clear external layer ; and in this way the movements 

 of the protoplasm are communicated through the pores to the 

 external layer, enabling the frustule, when in contact with 

 smooth surfaces, to glide along, with undulating motion, not 

 unlike a snail. 



Below is given a list of one hundred and ten species, comprised 

 in thirty-one genera. Many more, no doubt, will be found, as 

 the number of practical microscopists increase in the country. 



In conclusion, I beg to acknowledge the many obligations I am 

 under to Prof. Bovell, of Trinity College, and the Kev. W. A. 

 Johnson, of Weston, Ont. ; from both these gentlemen I have 

 received much valuable assistance, especially in the use of books 

 and microscopical apparatus. 



EPITHEMIA, KUTZ. 



E. tu7^gida, Sm. — Common. Grenadier Pond ; Sandy Cove. 



U. granulata, Kutz. — Rare. Grrenadier Pond. 



U. zebra, Kutz. — Rare. Desjardin Canal. 



U. gihha, Kutz. — Common. Humber Ponds. 



U. veiitricosa, Kutz. — Not uncommon. Kempenfelt Bay. 



U. argus, Sm. — Rare. Desjardin Marsh ; Burlington Bay. 



U. ocellata, Kutz. — Rare. Grenadier Pond. 



U. sorcx, Kutz. — Rare. Ditch at Ancaster ; Don River. 



U. jprohoscidca, Kutz. — Numerous. Stream near London. 



EUNOTIA, EHR. 



E. arms, Sm. — Numerous. Cedar Swamp, Weston ; Humber 

 Bay. 



E. tetrodon, Ehr. — Rare. Desjardin Canal. 



CYMBELLA, AG. 



C. Elirenhergii, Kutz. — Not uncommon. Grenadier Pond ; 

 Desjardin Canal ; Ton River. 



C. macidata, Kutz. — Rare. Stream at Niagara Falls. 

 C. Scotica, Sm. — Rare. Grenadier Pond. 



AMPHORA, EHR. 



A. ovaUs, Kutz. — Common. Grenadier Pond ; Sandy Cove } 

 Lake Simcoe. 



