PLANARIA NIGRA. 37 



temperature ; and secondly, from it not be- 

 ing improbable, that the number of margi- 

 nal specks is augmented with age. 



Superficial observation of such diversities 

 only create embarrassment; for as the shades 

 of distinction are fainter, there is the more 

 difficulty in condescending on, or rejecting 

 identity. The planaria, Proteus like, in- 

 cessantly assumes a variety of forms and 

 appearances, which, without due and care- 

 ful appreciation, will lead the naturalist far- 

 ther and farther from the truth. 



Planaria Panniculata, Fig. 6. 7. There 

 is a species of planaria, narrowly resembling 

 the former in size and figure, but different 

 in colour, and frequenting different aquatic 

 plants, on which it always appears as hav- 

 ing enjoyed a copious supply of food. When 

 recently taken, it is of a flattish semi-cylin- 

 drical shape ; the head forms an obtuse tri- 

 angular outline, and is smaller than the bo- 

 dy ; and the neck is smaller than the head. 

 The whole animal is of a deep dusky brown, 



