28 PLANARIA NIGRA. 



visible, of a jet black colour, seated in a 

 pale ground. Other experiments corrobo- 

 rated the fact; whence, one characteristic of 

 the species under discussion, is a row of nu- 

 merous minute black specks or eyes, situ- 

 ate in the very margin of the anterior part. 

 The same reserve in ascribing the faculty 

 of vision to these specks, is as necessary in 

 this instance as before ; nor can we affirm, 

 on denying them that peculiar province, 

 that they are void of all analogy to spira- 

 cula, or organs connected with respiration. 

 A subsequent examination of those plana- 

 riae just mentioned as a possible variety, 

 shewed that the head is sometimes so light, 

 as faintly to expose the site of the specks. 

 Thus, if the genus is to be partitioned ac- 

 cording to the presence or absence of eyes, 

 the black planaria will be removed from the 

 placft hitherto assigned to it. 



In the course of my earlier observations 

 on this animal, many unsuccessful experi- 

 ments were made to discover its food, which 

 seems chiefly derived from the under sur- 



