FLANARIA GRAMINEA. 119 



ny, both with the naked eye and magni- 

 fiers, to discover the wonted aperture of 

 the mouth in the surface of the belly. The 

 position of such an aperture, known under 

 the name of a ventral pore, is, as before re- 

 marked, a principal feature in the organiza- 

 tion of planariae. There were few vegeta- 

 bles in the water containing those of which 

 I speak, nor any approaches to maceration, 

 neither did it include the decaying remains 

 of animal substances ; and meanwhile the 

 planariae, contrary to the nature of all that 

 had been previously examined, continued 

 equally plump and large as when originally 

 taken. From this it was probable that they 

 did not subsist on vegetable aliment ; and 

 their constant action as if in pursuit of prey, 

 inferred that it might consist of aquatic ani- 

 malcula. The head in their courses, was 

 frequently directed against those that lay 

 in the way. They long rejected every dif- 

 ferent substance presented, until supplied 

 .with the soft parts of oyster, which had pro- 

 ved so grateful to the rest. Then, when in 



