122 DEPARTMENT OF THE XATAL SERVICE 



5. Diatoms from lake mud — Cobalt, O'Stxhio.— -Concluded. 



" scutelloides Sm. 

 " vindis Kg-. 

 Nitzschia sigma Ktz, 



" tryhlionella Han. 

 Pleurosigma atteivuatum W. Sm. 

 " ' hippocampus? 

 " acuminatum. 



Raphalodea (Epithemia) mitsculiis. 



" gihha. 



Stauroneis anceps Ehr. 

 " acuta W.S. 



" phoenicenteron Ehr. 



" punctata. 



" ventricosa. 



Surirella splendida Ehr. 



" elegans Ehr. 

 Synedra ulna Ehr. 

 Tahellaria floculosa Ivutz. 

 " fenestrata Ktz. 



This is a fresh-water and recent deposit, of interest on account of its high north- 

 ern latitude. It is very rich in Naviculse and also in Cymatopleux-ie, though no new 

 forms were recognized. It is probably representative of most of the similar deposits 

 in the extreme northern parts of Canada. 



6. Dlxtoms from Georgian Bay — Dredging 36 feet, 1912. 



(Lengths and breadths are given in microns, without and with brackets respectively.) 



Amphiprora ornata Bailey. 

 Am,pkora ovalis Ktz. 60, 84. 

 Campylodiscus (near decorus Breb.) 102, 105. 

 Cyclotella (?) 



Cymatophura elliptica (Breb.) W. Sm. 144 (62). 

 " " forma spiralis. 146. 



Solea (Breb.) W. Sm. 

 Oymhella lanceolata E. 100. 

 Epithemia Argus Ktz. 60, G6. 



" gihha Ktz var. ventricosa. 



Eunotia m-orhodon E. 60. 

 Melosira crenulata Ktz. 5 (Y), 5 (8). 



" varians Ag. ? 

 Navicula nohilis E. 162 (38). 

 " radiosa Ktz. 84 (12). 

 Smithii Breb. 60 (36). 

 Pleurosigma acuminatum (Ktz) Grun. 200 (20), 



attenuatum W. Sm. 300 (30). 

 Stauroneis Phoenicenteron E. 110 (38). 



" Gregorii Ralfs. ? 



Stephanodiscus Niagarae E. 

 Surirella elegans E. 240. 



rohusta E. 194 (72). 

 " splendida Ktz. 196 (52). 



