On the Sponge-fauna of Norway. 241 



RJiabdopleura by differences probably ordinal in value, and 

 which in some of its characters and in general appearance 

 resembles the ordinary Phylactolamiata. 



It is unnecessary to insist on the interest that must attach 

 to such a form should it exist. I trust that this notice may 

 meet the eye of some one who may have the opportunity of 

 searching the locality from which my father's specimen was 

 obtained, and to whom the point to be solved may appear of 

 sufficient importance to warrant a thorough investigation. 



XXV. — The Sponge fauna of Norway ; a Report on the Rev. 

 A. M. Norman's Collection of Sponges from the Norwegian 

 Coast. By W. J. Sollas, M.A., F.G.S., &c. 



[Continued from p. 144. J 



[Plates X., XI., XII.] 



Order TETRACTINELLIDA, Marshall. 



Tribe PACHYTRAGIDA, Carter. 



Group Geodina, Carter (Family Geodiidce, O. Schmidt). 



Genus 1. Geodia, Lmk. Type G. gibberosa, Lmk. 

 (Pyxitis, Sdt.) 



2. Cydonium, Fleming. Type C. zetlandicum, Johnst. 



(Geodia, auct.) 



3. Pachymatisha, Bwk. Type P. Johnstoni, Bwk. 



4. Caminus, Sdt. Type C. Vidcani, Sdt. 



5. PlACOSPONGiA, Gray. Type P. melobesioides, Gray. 



The sponges belonging to the group Geodina have been 

 known to naturalists for nearly two centuries, though for the 

 greater part of this time they were lost in that chaotic assem- 

 blage which formed the genus Alcyonium. It was in 1815 

 that Lamarck* defined, under the name of Geodia, the first 

 genus of the Geodine group ; but so powerful a hold had the 

 imaginary Alcyonian character of these sponges upon the 

 minds of the zoologists of those days, that even after the 

 generic distinctness of Geodia was perceived it was still retained, 



* Mem. du Mus. d'Hist. Nat. i. p. 333, 1815. 



