conspicuous and confluent with the colonial mucilage; cell contents 

 nearly colorless to light blue-green, homogeneous. 



This genus should be compared with Ankistrodesmus in the Chlo- 

 rophyta. Cells of some species are shaped very similarly, but differ- 

 entiation can be made on the presence of the chloroplast, which in 

 Ankistrodesmus, however, is often indefinite. Most species of Anki- 

 strodesmus have a pyrenoid which can be detected even though 

 the chloroplast is indistinct. 



Key to the Species 



1. Cells stout, not more than 5 times their diameter in length __ D. Smithii 



1. Cells elongate, needle-like, with apices sharply pointed or much 

 narrowed and narrowly rounded 2 



2. Cells much twisted about one another to 



form fascicles or bundles _.._ D. fascicularis 



2. Cells not twisted about one another 3 



3. Cells lunate, arcuate or sigmoid, sometimes 



nearly straight; apices rounded ___ D. rhaphidioides 



3. Cells straight, needle-hke, sharply pointed at the apices D. acicularis 



Dactylococcopsis acicularis Lemmermann 1900, Ber. d. Deutsch. 



Bot. Ges., 18, p. 309 



A free-floating colony of few (rarely solitary) acicular or straight 

 cells with extremely finely pointed poles, inclosed by a wide gela- 

 tinous envelope; cells 2-3/x in diameter, 45-60- (80)/;, long. 



Euplankter. Rather rare but found in several lakes. Wis. 



Dactylococcopsis fascicularis Lemmermann 1898d, p. 153 



PI. 105, Figs. 10-12 

 Colonies fusiform, composed of 4-8 elongate, arcuate or spirally 

 sigmoid cells tapering to fine points at the poles, rather compactly 

 twisted and inclosed by a thin, mucilaginous envelope; cells 1.5-2/^ . 

 in diameter, 19.5|a long. 

 Euplankter. Wis. 



Dactylococcopsis rhaphidioides Hansgirg 1888b, p. 590 

 PL 105, Figs. 13-15 

 Cells elongate-fusiform, seldom straight, usually arcuate or sig- 

 moid, narrowed but not sharply pointed at the poles, arranged in 

 colonies of 4-8 within a hyaline, gelatinous envelope; cells IS/x in 

 diameter, 5-25/x long. 



From squeezings of Utricularia. Mich., Wis. 



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