190 



THE AMERICAN MONTHLY 



[Juue 



mination with a magaificatiou of two or three hundred 

 diameters. 



I have been able to identify and to mount in Canada 

 balsam, and also dry, the following 58 species of the 

 Diatomaceae in this one gathering, of which over 40 may 

 be seen on a single slide under a § in. circular cover 

 glass : — 



Plearosigma attenuatum 

 ' ' lacustre 



' ' spencerii 



Nitzschia sigmoidea 

 " parvula 

 " amphioxys 

 Tryblionella augustata 



' ' gracilis 



Rurirella biseriata 

 ' ' ovalis 

 ' ' linearis 

 Pinnularia viridis 

 " viridula 



" oblouga 



' ' gracilis 



" acuta 



" radiosa 



Navicula cuspidata 

 •' firma 



" amphisbsena 



" elliptica 

 " gibberula 



" inflata 



" aflSnis 



" cryptocephala 



" binodis (?) 



" bleischii (?) 



" veneta (?) 



" producta 



Navicula tumida 

 Stauroneis anceps 

 Cymatopleura solea 



' ' elliptica 



" apiculata 



Cymbella cuspidata 

 Amphora ovalis 



' ' luinutissima 

 Diatom a vulgare 



" elougatutti 

 Odontidium harrisonii 



" mutabile 



" paraaiticum 



Denticula sinuata (?) 

 Gomphonema curvatum 



' ' constrictum 



Cyclotella kutziugiaua 

 Coccoueis placentula 

 Syuedra ulna 

 Cocconema lanceolatum 



' ' cistula 



" cymbiforme 



Encyonema prostratum 



' ' ciespitosum 



Achuauthes exilis 

 Eunotia mouodon 

 Melosira varians 

 Fragilaria capucina 

 Colletonema neglectum 



This time of year and want of rain were not favorable 

 for Desmids, but I came across a few vigorous specimens 

 of the following species : — Closterium striolatura (show- 

 ing very clearly the phenomena of cyclosis and so-called 

 'swarming of the granules' at its extremities), Pediastrum 

 granulatum, Cosmarium botrytis, while among the less 



