OBSERVATIONS OF SIR JOHN DALYELL. 87 



vulsive motion among the tentacula of a Hydra on 

 the evening of the 14th, apparently from a Medusa 

 having been seized by its arms. The like occurred 

 next morning, when another Medusa was apparently 

 liberated from like thraldom. 



Similar convulsive movements agitating the same 

 Hydra during the 16th, it was brought under close 

 inspection, for being unable to discover the like 

 spasmodic demonstrations among its companions, at 

 least 100 in number, it seemed surprising, that amidst 

 such a host of enemies, mercilessly devouring what- 

 ever they could master, the Medusa should live with 

 impunity involved by the very organs of capture. 



On dislodging the subject of this observation, ap- 

 parently a Hydra of medium size, with scissors, and 

 transferring it to a watch-glass, nothing but the 

 wonted convulsion which proceeded from the clasping 

 of the arms of a Medusa upon the disc or extremity 

 of the Hydra was seen on the morning of the 17th. 

 However, several little Medusae were swimming at 

 large next day ; the size of the Hydra had diminished, 

 it was visibly indented with deep corrugations, and 

 when closely examined, proved to be wholly composed 

 of Medusae, in various stages of development. The 

 arms at the summit belonged to the animal which 

 was most mature. Many more in the lower part of 

 the series soon became active, and beneath them still 

 more were perceptible, as yet in a state of absolute 

 quiescence and indefinite in form (PI. I. fig. 5, h). 

 Seven advancing Medusae in all might be enumerated 

 in the mass in the course of this day, the 18th of 

 February. 



