Dr. G. J. Allman on the Freshwater Zoophytes of Ireland. 329 



view when he established the genus ; but the latter would cer- 

 tainly be better removed and placed in a genus by itself. 



To this conclusion, my observations on the freshwater Zoo- 

 phytes had induced me to arrive, and indeed the above passage 

 had been written when I happened to meet in the ' Comptes 

 Rendus^ with an abstract of a memoir by M. Gervais on the 

 freshwater Zoophytes of the neighbourhood of Paris. I was 

 pleased to find that in Gervais' s memoir he had taken the same 

 view of the subject with myself, and that for a Zoophyte with 

 a circular disc, found near Paris, and which he considers iden- 

 tical with Tuhularia Sultana of Blumenbach, he has constituted 

 a new genus, giving to it, in honour of Frederic Cuvier, the name 

 of Fredericella. To Gervais then is due the first accurate dis- 

 crimination of the species originally included under the genus 

 Plumatella, and their distribution between two distinct genera; 

 and as this dismemberment of the original genus is founded on 

 strict zoological principles, I shall unhesitatingly adopt it, parti- 

 cularly as I had myself arrived at the same conclusion without 

 any knowledge of Gervais' s researches. The Zoophytes then at 

 present included under Plumatella I shall distribute between two 

 genera, retaining under Plumatella those with crescentic discs, 

 and removing to Fredericella those whose discs are circular. 



An important addition to the British genera is Paludicella. 

 This term was given by Gervais to a freshwater Zoophyte ori- 

 ginally discovered by Ehrenberg, and called by the latter Al- 

 cyonella articulata. For the addition of this interesting genus 

 to the British fauna we are indebted to Wm. Thompson, Esq., 

 who found the polypidom cast on shore at Lough Erne in August 

 1837 ; and I have myself since obtained living specimens in the 

 Grand Canal near Dublin, and have been enabled fully to establish 

 its identity with the continental Zoophyte. 



Paludicella, of which but a solitary species appears to have been 

 discovered, is a Zoophyte of much zoological importance. While 

 it possesses many points of structure which naturally connect 

 it with the other ascidioid lacustrine Zoophytes, it is at the same 

 time characterized by certain peculiarities which approach it to 

 the marine species, and which I conceive sufficient to justify me 

 in assuming Paludicella articulata as the type of a distinct family 

 among the lacustrine Zoophytes. 



In October 1842 1 discovered in the docks of the Grand Canal 

 Dublin, a hydroid Zoophyte of much interest. It is referable to 

 no known genus, and occupies a position between Coryne and 

 Hermia. For the reception of this Zoophyte therefore I have been 

 obliged to form a new genus, to which I have given the name 

 of Cordylophora. 



I have now found in Ireland all the species of freshwater Zoo- 



