473 



of branched prostrate tubes, with a transparent slit-like line 

 which runs along the length of their free surface, and gives an 

 eraarginate appearance to the orifices. Polijpide, with about 

 fifty tentacula. Hab. Attached to various fixed objects in 

 stagnant and slowly running waters. 



Alcyonella Jiabellum was now for the first time recorded 

 as a member of the British fauna. It was originally disco- 

 vered by Professor Vanbeneden, in the neighbourhood of 

 Brussels, and was now found by Dr. AUman, attached to a 

 piece of timber taken out of a pond at Reading, and commu- 

 nicated by Mr. Bowerbank along with specimens of A. fun- 

 gosa. 



The third section was devoted to the consideration of the 

 anatomical details and natural affinities of the genus. 



The old notion, which by mistaking the zoological rank of 

 the bryozoa, erroneously referred them to the class of polypes, 

 caused the same terms to be applied to them which were also 

 used to designate the various parts of the true polypes. The 

 recognition, however, of a type of structure totally distinct 

 from that of the true polypes necessitates a change in the ter- 

 minology employed in their description. On these grounds 

 Dr. Allman ventured to substitute some new terms for those 

 previously used, while an additional number of such terms is 

 demanded by our increased knowledge of their structure. For 

 the term polype originally applied to the digestive canal with 

 the tentacular crown of a bryozoon, and now no longer admis- 

 sible, that of polypide was substituted; to the external com- 

 mon horny calcareous investment, which was originally toge- 

 ther with the solid basis of the genuine polypes known under 

 the names of polypary and polypidome, but which is really 

 the homologue of the shell in the higher moUusca, the name 

 of SyncEcium was given. The internal membranous sac was 

 called Pallium or Mantle, — a name suggested by its real im- 

 port, for it is manifestly homologous with the organ of the 

 same name in the higher mollusca. To the sort of stage 



2 N 2 



