Deux Hydres d'eau douce :

 

 

 

Hydra vulgaris

L'Hydre vulgaire

[20 mm]

 

 

 

 

 

 

 

 

 

 

 

 

 

 

                        

                                                                                                                                                                                                                                             

Hydra viridissima

L'Hydre verte

[8-10 mm]