ON THE 



NATURAL HISTORY 



OF 



PEOTOCOCCUS PLUVIALIS, Ktjtz. 



Eamatococcm pluvialis, Yloiaw, 

 Chlamidococcus versaiilis, A. Braun, 

 Chlamidococous pluvialis, Motow and A. Braun. 



The author commences his paper by referring to the 

 observations of Flotow, on the same subject, under the 

 name of Hcematococcus pluvialis, ('Nova Acta Ac. C. L. 

 C. N. C.,' vol. XX, p. 11,) and to which he assigns the 

 highest merit. He proceeds to give an abstract of 

 Flotow^'s observations as an introduction to his own. 



However various the metamorphoses undergone by the 

 Hcematococcus in the course of its development, they 

 may, nevertheless, be referred to two principal forms, — 

 the still and the motile. The former, H. pluvialis quies- 

 cens, forms a sort of crust on the margin and bottom of 

 the vessel in which it is kept ; the other, II. pluvialis, 

 swims about in the water. 



The motile form is from 0-0003 to 0-0012 of a Paris 

 inch in diameter, and consists of a colourless mucous 

 envelope, probably open in front, within which is con- 

 tained the true mother-cell, and which is either centric 

 or excentric. The contents of the latter are grumous 

 and vesicular, and either altogether of a carmine red 



