116 PL AN ARIA GRAMINEA. 



Cation of genera creates, it is now retained 

 as constituting a second division of the ge- 

 nus planaria. The distinction is principal- 

 ly founded on the shape of the animal, the 

 position of the mouth, and number of eyes. 

 The planaria graminea is of a beautiful 

 grass green colour, and by the aid of a 

 magnifier, perceptibly speckled with black ; 

 but to the naked eye, the surface of the 

 skin is uniformly green. Its figure is a 

 double cone, truncated at one extremity 

 the head; and the termination of the tail is 

 the opposite apex. Thus the planaria is not 

 flat, and the head is obtuse. Near to the 

 termination of the truncated part are two 

 very black specks or eyes, far asunder, one 

 being on each side of the head. I have not 

 been able positively to ascertain whether 

 there are none other of smaller size; for it is 

 not impossible that, under favourable circum- 

 stances, the most powerful magnifiers might 

 bring such into view. In the leech, at least, 

 with respect to certain species, particular 

 difTiculty sometimes attends the discovery 



