ANALYTICAL INDEX. 



Page. 

 CERTAIN aquatic animals enjoy singular prerogatives, . 1 



Planariae, 3 



General characteristics, 4. 



Apparently akin to the leech and the snail, ib. 



The genus admits of subdivisions, ib. 



Planaria Flexilis, 5 



Specks or eyes, 6 



Difficulty of microscopical observations, which should 



be made by day, 7 



The nature of vision is obscure in the Mollusca and Ver- 



mes, 8 



Planariae in general court the light, 9 



The size of the Flexilis is affected by food and tempera- 

 ture, 10 



It is carnivorous, 11 



The whole body is discoloured by the food, 12 



Errors inseparable from superficial observation, .... 13 

 The grosser parts of food are distributed throughout the 



body, 15 



This animal is extremely voracious, 16 



It perishes from inordinate feeding, 17 



Remarks on the Polypus and Actinea, 18 



The Planaria Flexilis dwells in society," 19 



Mode of obtaining and preserving aquatic animals, . . ib. 



Propagation of the Flexilis, 20 



Artificial sections become perfect animals, 21 



Planaria Nigra, 22 



It is tenacious of life, . .... .26 



