1899] MICROSCOPICAL JOURNAL. 93 



the others were without. Very many were aggregated into 

 dense masses. The water abounded with independent in- 

 dividuals traveling in every direction, and also with minute 

 spore-like forms of the same color as the diatoms and which 

 were also actively motile. It was impossible for me to de- 

 cide upon the species of these minute forms. In some cases 

 even the genus is doubtful. In my article in the December 

 number of this Journal, the printer makes me say as to 

 similar forms that they were of "well-known" species. I wrote 

 "unknown." These forms are mostly rounded even when 

 elongated, with no sharp angles and with slight markings, 

 without silex, and can be known as diatoms only by their 

 color and motions. Some of the Navicula and the Nitzschia 

 resemble each other so closely at this stage as to be easily 

 mistaken. Although the original diatoms of this material 

 were nearly all Pleurosigma, yet nothing developed that 

 could be recognized as that genus. I had one bottle filled at 

 Morgan Point rocks projecting into the Sound outside the 

 Lighthouse Point. This I poured into a large tumbler which 

 it just filled. It had little sediment but diatoms, — Synedra, 

 Melosira, Navicula maculata and other large varieties. In 

 a few days, a number of delicate and beautiful bright green 

 algse started and grew rapidly. These were possibly Clado- 

 phera refracta, but they did not attain sufficient maturity 

 for me to decide with certainty. Soon a red Schizonema ap- 

 peared upon the branches and finally attained more than an 

 inch in height. It was of beautiful rosy pink in color and 

 had a flattened, much-branched frond filleded with diatoms. 

 In this stage, it made a splendid object for the microscope. 

 I have always keenly regretted that I did not sacrifice it for 

 slides, but I wanted to study its development. Other 

 branches showed a light-golden brown fringe. This was a 

 very delicate Acnauthes with long stipe, as long in propor- 

 tion as that of Acnauthes longipes, but the diatom was 

 scarcely one-tenth as large. 



One morning, when the algse had grown nearly to the top 



