﻿Dec, 1856.] 



ELLIOTT SOCIETY. 



63 



weight of the body is thrown first on one side and then on the 

 other in progression. 



This is the motion of Turritopsis when performing a long jour- 

 ney, but he may be often seen sporting about the surface, taking a 

 few side-long leaps like those described, and then, with the mouth 

 of the bell downwards, expanding himself to the utmost, all his 

 tentacula, which in progression were tightly curled up, now gradu- 

 ally disentangling and stretching themselves to their greatest 

 length, turned upwards or horizontally, while the motionless para- 

 chute slowly sinks to the bottom. However, the tentacula thus 

 extended seem to be keenly alive to every passing particle, and 

 every now and then one or two or more of them may be seen to 

 contract with great rapidity, as if they had come in contact with 

 something to be seized or avoided. At this time the Turritopsis 

 has spread all his snares, and his tentacula radiating on all sides, 

 form a circle probably equally efficacious with the spider's web. 

 Indeed, 1 have found small Crustacea, their principal food, fre- 

 quently dead or dying in the embrace of these tentacula, or rather 

 simply hanging to them by invisible attachments, illustrating in 

 another instance the deadly properties of those wonderful thread- 

 cells. After, however, the Turritopsis has been sinking for some 

 time, (he may even allow himself to touch the bottom of the jar,) 

 he suddenly draws in, more or less, all his tentacula, and beats up 

 again towards the surface in the same old zig-zag way, now and 

 then running along for a little distance in a horizontal direction, 

 but generally going quite up to the surface, and there expanding 

 himself, mouth downwards, again to sink slowly towards the bot- 

 tom. The animal may continue fishing in this way a whole morning. 



I come now to treat of that part of the history of Turritopsis 

 which is most full of interest. I mean its development. I believe 

 that, up to the present time, nothing is known of the embryology 

 of those genera, associated by Forbes in his family^of Oceanidae, 

 except some fragmentary observations on Oceania Jtavidnla, by 

 Gegenbaur, (which I have not seen,) and the few though impor- 

 tant observations of Gosse, on the re-production of Turris neglecta. 

 These latter showed that the ovum of Turris is cast a planule, 

 becomes elongated, forming a creeping root attached to some- 

 object, and that from it, in a short time, a four-tentaculated hydra 

 shoots up. This establishes the fact that, in its first stages, the de- 

 velopment of Turris is like that of all other known Naked-eyed 



