104 THE AMERICAN MONTHLY [Apr 



shade where the sun does not strike it. It is also very, 

 very small, so that when examined with a quarter-inch ob- 

 jective, which magnifies about four hundred diameters, it 

 can just be seen, and would not be observed at all were it 

 not in constant motion, moving about like a little canoe 

 or boat, first one way and then the other. It is also seen 

 when living to be marked with one or two oil-spots in its 

 interior. These are known as oil-spots or oil-dots and 

 what they are is problematical. I think they are the rep- 

 resentatives of ovaries. They are where the ova or ger- 

 minal dots or spots appear. Although they are so small 

 and it is, therefore, difficult to ascertain exactly what they 

 are and what they form, I think that the ova, if they can 

 be called so, appear there. On account of their being 

 composed of oil-like substance, they appear (when exam- 

 ined by means of the microscope) when the Bacillarian 

 is swimming around in the water. They are of a differ- 

 ent (higher) refractive index, than is the surrounding water 

 and appear bright. 



This is tn"e appearance of the Bacillarian. At first it is 

 not so clearly seen for the oil globules are not formed. 

 Subsequent thereto there appear in the cell-contents of 

 the Bacillarian certain minute dots which one just sees to 

 be active, rushing and pushing about in violent motion. 

 These are oil-like also, although not so much so as the oil 

 globules. Their presence and what they are have also 

 caused wonder and why they are there has not been con- 

 ceded, but I think they are anthozoa or what are so- call, 

 ed and are male organs. At least, (but how we know 

 not), they impregnate the other oil-globes, and these be- 

 ing impregnated burst the shell of the Bacillarian and es- 

 cape to find a new colony of Bacillarians. 



This commonly takes place, in the spring,in this region. 

 In other regions where there is not such a change of tem- 

 perature from winter to summer, for it is this change 

 which marks the existence of Bacillaria, it is true of 



