82 THE AQUARIAN NATURALIST. 



CHAPTER VIII. 



" Nothing of him that doth fade, 

 But doth suffer a sea-change 

 Into something new and strange." 



HOW THE HYDRvE TUB.E PRODUCE MEDUSAE. 



WE have hitherto viewed the Hydra tuba as an 

 animal apparently perfect in itself and sustaining an 

 independent life. A creature which survives for years, 

 which transmits its form,, together with all its pecu- 

 liarities, to its immediate progeny and to remote 

 descendants, seems certainly, at first sight, entitled 

 to a distinct position in the zoological series ; but we 

 have still to look farther, to dive deeper into the 

 strange history of this wonderful production, before 

 pronouncing as to its real nature. 



At certain seasons of the year, that is, as far as we 

 know at present, during the months of February and 

 March, the Hydra tuba, if well-fed and vigorous, 

 begins to exhibit an extraordinary elongation of its 

 body, and gradually increases in size, until it is evident 

 that some great change is in preparation, and in a 

 short time numerous transverse folds begin to make 

 their appearance at equal distances, one below the 

 other, partitioning off the body into numerous rings 

 or segments (PL I. fig. 5,d). 



