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PROCEEDINGS OF THE 



[Dec, 1856. 



Medusae. In confirmation of this Gegenbaur asserts, that the 

 nurses of Oceanidae, so far as known, are Syncorynidae. Not so, 

 however, with the embryological history observed in Turritopsis. 

 Here I have encountered a chapter in nature so full of interest, so 

 beautiful in many respects, and yet, at the same time, so novel 

 when compared with our former knowledge of the class, that I 

 think I should have been slow to believe it, had it not unmistake- 

 ably passed before my own eyes. 



In the early part of July I found the first full-grown specimens 

 of Turritopsis. Among them was one somewhat larger, perhaps, 

 than the rest, which I took with the bell inverted. When placed 

 under the microscope, conceive my astonishment to find, clinging 

 to the bell and sides of the proboscis, numerous little animals of 

 singular aspect, each of which appeared to be sustaining his hold 

 by a four-legged pedestal, and to be writhing about in the water a 

 long appendage, the meaning of which I could not understand. In 

 a very few moments, however, in spite of the difference in propor- 

 tion of parts, the resemblance of these beings to the free young 

 hydra of Tubularia was unmistakeable, and though at the time I 

 entirely mistook the oral end of the body for the stem-end, and the 

 stem-end for the oral, yet a field of research was open to me in an 

 instant, which, from the peculiarity of the circumstances only, I 

 felt must be full of extreme interest. 



It was not until the 15th of August, that I again encountered the 

 same phenomenon, in a smaller size of Turritopsis, of which quite 

 a number were taken. I found the cavity of the bell around the 

 proboscis occupied again by these larvae, but besides those formerly 

 observed, were others, which were Gradually becoming Medusas, 

 and still others which had assumed the Medusa-form already, and, 

 lastly, to complete my satisfaction, I saw them, after expulsion 

 from their former abode, swimming about freely in the water with 

 the rythmical contractions of Medusae. 



It was quite plain from this, that expulsion had taken place, but 

 still I had not seen the expelled animals until some time after the 

 occurrence, and it was not until a later date, Sept. 18th, that I had 

 an opportunity of observing the condition of the larva at the time 

 of expulsion. From this I learnt that, shortly after assuming in- 

 dependence, the larva changes the Medusa form, under which it is 

 first freed, for another which is more persistent, so that here again 

 was a phasis of much interest to the systematise 



