142 CONCLUSION. 



However, it is not ascertained that such a 

 property is common to every species. Pro- 

 pagation is effected in two distinct modes, 

 void of any relation or analogy to each 

 other ; being either by an egg containing 

 one or more young, or by the spontaneous 

 separation of a fragment of the tail, which 

 becomes a perfect animal. But no disjunc- 

 tion of parts takes place in those spe- 

 cies producing eggs, nor have eggs been 

 discovered where the race is perpetuated 

 by separating fragments. The reproduc- 

 tive principle is enjoyed in the highest per- 

 fection by the genus, whereby not only the 

 most dreadful lacerations are speedily heal- 

 ed, but wanting portions are repaired, and, 

 by a strange anomaly from the laws of or- 

 ganic life, the duplication of essential organs 

 may be artificially obtained. 



The preceding remarks are far from ex- 

 hausting the history of planariae. Pheno- 

 mena equally singular and interesting are 

 displayed by other species inhabiting the 



