PLANARIA GRAMINEA. 121 



of the graminea, therefore, remove it .from 

 the same division of the genus comprehend- 

 ing those provided with a prohoscis ; and 

 there is still another line of distinction, in 

 the visible corrugations or inequalities 

 sometimes exhibited by the body, whereas 

 the others are perfectly smooth. Like 

 them, it swims supine at the surface of the 

 water. 



These planariae are hermaphrodites, in 

 the strictest sense ; but whether impregna- 

 tion originally results from the sexual union, 

 may be called in question, not perhaps as 

 to the vivifying principle, but with respect 

 to the formation of the egg. 



Some years ago, the animal was not un- 

 common ; and in the course of casual in- 

 spection, I had frequently remarked an egg 

 within the body ; in as far as recollection 

 serves, the species was the same. Its su- 

 pervening rarity, however, of later years, 

 partly arising from the progress of agricul- 

 ture, so inimical to the pursuits of the na- 



