472 



of fresh-water zoophytes are only particular phases of deve- 

 lopment of Alcyonella, a doctrine for which it seems only ne- 

 cessary to compare these different forms with one another to 

 convince ourselves of its utter groundlessness. 



In the same year with the appearance of Raspail's me- 

 moir, Meyen published in the Isis a paper entitled " Natur- 

 geschichte der Polypen." In this paper the Alcyonella is de- 

 scribed and figured, but the description and figures are in seve- 

 ral cases erroneous, and the chief value of the paper is to be 

 found in the announcement that the animal gives birth to free 

 ciliated embryos, — a fact of great interest in connexion with 

 similar discoveries which had been made among the marine 

 representatives of the order. 



After this we find the names of Ehrenberg, Gervais, 

 Dumortier, and Vanbeneden, on the Continent, and in these 

 islands, Teale, Johnston and Dalyell, all connected with the 

 history of the genus. Vanbeneden, especially, has given us 

 some most important memoirs, and has added a new species 

 to the genus, which up to his time consisted of but a single 

 specific form. This new species Professor Allman has within 

 the last few months discovered upon a piece of timber, along 

 with specimens of the old species, A. Fungosa, from the 

 neighbourhood of Reading, communicated by Mr. Bowerbank. 



In the second section of the memoir containing the des- 

 criptive zoology of the genus, the following generic and speci- 

 fic characters were given. 



Genus Alcyonella. Lamarck. 

 Char. Lophophore crescentic. Synoecium composed of 

 tubes adhering to one another by their sides. 



Number of species, 2. 



1. A. fungosa, FaWas. Char. Synoecium iungoidjormed of 

 numerous branched vertical tubes with entire orifices. Tenta- 

 cula about sixty. Hab. Attached to various fixed objects in 

 stagnant and slowly running waters. 



2. A. fabellum, Vanbeneden. Char. Synoecium, formed 



