PLANARIA FELINA. 43 



part abounding with aquatic vegetables, and 

 rarely in springs, there is found a dark 

 brown planaria, of uniform colour, which at- 

 tains considerable size. The largest which 

 I have seen, were at least five-eighths of 

 an inch in length, and somewhat less than 

 one in breadth ; but in general they are 

 smaller, perhaps not above one in a thou- 

 sand being of these dimensions. The co- 

 lour is lighter than that of the panniculata, 

 but some are of a dull, dark, dirty brown. 



The figure of the animal differs from that 

 of the two former species ; therefore, if we 

 are to found on slight external discrepan- 

 cies, a division of the genus may be made, 

 including it, and others of similar organi- 

 zation, particularly with regard to the specks 

 or eyes. By this latter characteristic, it is dis- 

 tinguished from the two subsequent species, 

 to which it is allied by shape, and united to 

 the two preceding. A short triangular 

 tentaculum, or feeler, terminates each side 

 of the head, susceptible of such contraction 

 and dilatation, as absolutely to disappear or 



