Mr. H. J. Carter on Peridinium cypripcdiuin. 40L 



Ehrenberg and Dujardin made by mixing- up the Trachelitis tri- 

 chophorus of the former, which is the Astasia limpida of the latter, 

 with the Euglence ; and have proposed that under the latter should 

 only be included Infusoria of the type Euglena, and under that 

 of Astasia the type only of Astasia limpida, — Euglena belonging 

 to the vegetable, while Astasia belongs to the animal side of the 

 boundary of the two kingdoms ; Astasia being colourless, pre- 

 senting an oral and an anal orifice, and taking in crude material 

 for food, while Euglena is for the most part green, presents no 

 oral or anal orifice, and cannot be seen to incept crude material. 

 There are other distinctions between these organisms; but ge- 

 nerally they arc so much alike that Dujardin placed the whole 

 under the head of Euglena; so that if the organization of Asta- 

 sia limpida were attributed to Euglena, the same erroneous view 

 respecting the organization of the latter would arise as that 

 which would be caused by attributing the organization of Uro- 

 centrum to Peridinium. Claparede has also some observa- 

 tions (p. 31G) bearing on the subject; but they were written 

 unknown to me, if not probably published subsequently to mine. 

 For my own, in extenso, I must refer the reader to the volume 

 of the c Annals' already mentioned. 



Now, Urocentrum Turbo bears a similar resemblauce to Peri- 

 dinium that Astasia limpida (Duj.) bears to the Euglena. Hence 

 the object of this communication. 



As yet, Peridinium must be viewed as closely allied to Euglena 

 (see my description of Peridinium sanguineum, which imparts a 

 red colour to the sea round the shores of the island of Bombay, 

 'Annals/ 1858, vol. i. p. 258). It has a large cilium, which 

 does not appear to be composed of a lash of hairs ; a reddish 

 eye-spot, which may be double or quadruple, according with the 

 number of divisions which the organism may be undergoing 

 within its lorica, but always connected with a hyaline space, 

 which in Euglena is seen to be the contracting vesicle ; a nu- 

 cleus, and vesicles of green or otherwise coloured chlorophyll 

 (see the communication to which I have last referred); but no 

 oral or anal orifice, and no appearance of being supported by 

 the inception of crude material for food. 



On the other hand, Urocentrum Turbo is colourless, has an 

 oral and probably anal orifice ; incepts crude material for food, 

 as pointed out by Prof. Clark; presents a circular and a median 

 groove, but with the crown of minute cilia not situated along 

 the line of the former, as in the cinctum of Peridinium, but in 

 front of it, and the large cilium, although issuing from the me- 

 dian groove, composed of a bundle of hairs, instead of a single 

 filament. Yet this organ serves to anchor Urocentrum, just as the 

 simple filament can arrest the progress of Peridinium, while the 



Ann. fy Mag. N. Hist. Ser. 3. Vol. xvi. 27 



