PLANARIA FLEXILIS. 



die of the belly or under surface ; swim- 

 ming supine." Another division may be 

 defined, " body in a state of repletion, re- 

 sembling a double cone ; mouth in the an- 

 terior extremity." 



Division I. Planaria Flexilis, Fig. 1, 2. 

 Near to low- water mark on the shores of 

 the Forth, we find a species of these ani- 

 mals, universally of a dull whitish or pale 

 ash colour, about an inch long, and a quar- 

 ter of an inch across at the extreme breadth. 

 The whole body is quite flat, especially be- 

 low, almost as thin as paper, and endowed 

 with singular flexibility. The head is se- 

 micircularlv obtuse; and, from near its ante- 

 rior extremity, the body decreases to the 

 termination of the posterior part or tail, 

 which is also obtuse, but proportionally much 

 less so than the head, and is sometimes dimi- 

 nished to a point. The contour of young 

 planarise tends to the outline of a spheri- 

 cal triangle, which gradually alters with 

 their increment. By an uncommon distri- 

 bution of the most important organs, the 



