20 LECTURE I. 



fore cannot be doubted that the Polypes do really 

 constitute the connecting link between animal and 

 vegetable life. 



The figures of the Polype, selected for our pre- 

 sent inspection, are from the work of the cele* 

 brated Roesel ; and represent with great elegance 

 and fidelity, the appearance of these extraordinary 

 animals, both in their natural size, and magnified 

 by the microscope. The species in these figures 

 of Roesel are the Green, the Brawn, and the 

 yellowish-Grey Polype. 



These most curious and interesting animals were 

 first fully described by a Monsieur Trembley, of 

 Geneva, who, about the year 1730, happened to 

 discover them in searching after some small aqua- 

 tic plants. They had indeed been discovered long 

 before by the celebrated Leewenhoeck, who gave 

 a general description of the animal, and observed 

 that it multiplied by an apparent vegetation ; but 

 it was reserved for Monsieur Trembley to discover 

 and describe, in an ample and circumstantial man- 

 ner, all its extraordinary properties. Monsieur 

 Trembley happened first to observe the small green 

 Polype, or Hydra viridis, and being greatly sur- 

 prised at the appearance of a creature, which had 



