38 JOURNAL OF THE [January, 



notice how little they are known, even among old microscopists. 

 Carpenter, on p. 702 of the 5th edition of his work on the 

 microscope, very briefly refers to them, and gives a very inaccu- 

 rate sketch of one which he simply calls Dennesfes, although this 

 genus embraces about a dozen species, none of which, as far as 

 I am aware, is characterized by these wonderful "arrow-hairs." 



