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tlierefore contented myself by sketching in my note-book, 

 the few imperfect external cliaracters which continued visi- 

 ble on the dry and shrivelled zoophyte. No farther than 

 this did my knowledge of Mr. Thompson's discovery extend, 

 when an opportunity fortunately occurred in October last, 

 of obtaining living specimens of the animal. These I dis- 

 covered in the Grand Canal, near Dublin, and have thus 

 been enabled to pursue my investigations, from which I 

 find the species to be one of great interest. I find, more- 

 over, that although it has been hitherto unnoticed, as a 

 British animal, it is identical with the alcyonella articulata 

 of Ehrenberg, for which Gervais, Avho found the animal near 

 Paris, subsequently constituted anew genus, under the name 

 of Paludicella.* It is also noticed by Van Beneden, who 

 met with it near Louvain, and gives a figure of it,t which, 

 though not very good, will yet be found of use in the iden- 

 tification of the species. Though Ehrenberg's appellation 

 possesses the claim of priority, yet, as it refers the zoophyte 

 to a genus into which its structure will not admit it, it must 

 be rejected, and I shall accordingly adopt the name Palludi- 

 cella, by which it has been designated by Gervais. 



" In the following remarks upon the muscular system of 

 the fresh water ascidian zoophytes, my description of this 

 system is chiefly derived from observations made upon Palu- 

 dicella articulata, as there are certain points in the muscular 

 anatomy of other species, upon which I cannot as yet speak 

 with certainty, and for completing my observations on which, 

 I must wait until the approaching Spring shall afford me 

 fresh objects for investigation. 



" In describing the muscles of these animals, I have 

 availed myself of Dr. Farre's phraseology, applying to the 

 several sets of muscles in the fresh water ciliobrachiate zoo- 



* Bulletin de I'Acad. Roy. de Bruxelles, an. 1839. 

 t Mem. de la Society d'Hist. Nat. de Paris, torn. 4. 



2 D 2 



