STUDIES ON THE OOMPAEATIVE ANATOMY OF SPONGES. 41 



Studies on the Comparative Anatomy of 

 Sponges. 



IV.— On the Flagellated Chambers and Ova of 

 Halichondria panicea. 



By 



Arthur Dendy, m.Sc, F.Ii.S., 



Demonstrator and Assistant Lecturer in Biology and Fellow of Queen's 



College, in the University of Melbourne. 



With Plate V. 



The purpose of the present short communication is, as indi- 

 cated in the title, to call attention to the minute structure of 

 the flagellated chambers and ova in the common British sponge 

 — Halichondria panicea. 



The material upon which my observations are based I owe 

 chiefly to Mr. Martin Woodward, who kindly gave me some 

 fine pieces of the sponge in question, collected by himself in 

 the English Channel. Some of the material thus obtained 

 was treated while fresh with osraic acid, to which fact is due 

 the excellent state of preservation. Material not so preserved 

 I find to be practically valueless for the study of the histology 

 of the chambers, which, indeed, can only be made out where 

 the osmic acid has penetrated before the death of the sponge. 



Part of the material was dredged by myself in the Solent, 

 and it was in sections of this that I first recognised the exist- 

 ence of SoUas's membrane in the species.^ The sections were 



^ " Studies on the Comparative Anatomy of Sponges," II, ' Quart. Journ. 

 Micr. Sci.,' December, 1888. 



