Contributions from the Cryptogamic Laboratory of Har 
yard University. XXIII.' 
Notes on the life history of a blue-green motile cell. — 
BRADLEY MOORE DAVIS. 
WITH PLATE XI. 
In view of certain opinions that have been expressed by 
some botanists, notably Hansgirg, but which most botanists” 
have not generally accepted, that there exist motile condi- 
tions of certain members of the MyxoPHYCE (CYANOPHY- 
CE#), the writer was much pleased when last November he 
happened to meet with a unicellular blue-green motile orga 
ism and was able to trace its life history. 
These blue-green motile cells were first noticed while e& 
amining some material collected from a pool in the salt | 
marshes of the Charles river, Cambridge. They appeal 
in such quantities in vessels holding the collections of Begge 
toa, Oscillatoria, Melostra, Cladophora, Enteromorpha clath 
rata, etc., fougd in the salt marshes, that they formed 
scum upon the surface of the water and sides of the vessels, 
where they readily passed into a non-motile stage. ~ 
source of the blue-green swarmers was soon traced to colonit 
of bluish-green cells, that resembled colonies of Polycyst 
and were found commonly adhering on the sides of ™ i 
grass (Spartina) and other objects. The measurements © 
these cells were identical with those of Polycystts pallida, ‘\ 
the colonies resembled strikingly the herbarium specimens © 
this species. . m 
_ Anton Hansgirg has been the most prominent champ 
of polymorphism among the Myxophycee. He has expe, 
himself as believing that species of Euglena? give mS® Oy 
cillatoria filaments and certain blue-green swarmers he thin 
a 
sr repared under the direction of Dr. W. 
Hansgirg, Botanisches Centralblatt 23: 
‘Hansgirg, ibid. 
G. Farlow. oe 
v4 ae 
1d. p. 230, ) 22. 188) 
Goebel, Outlines of Class. and Sp. Morph. of Plants (Engl. trans: i 
32. 1885. 
