296 A MONOGRAPH OF THE AUSTRALIAN SPONGES, 



Numerous small pores lead from the inhalent canal into the side 

 opposite the circular and comparatively very small exhalent pore 

 or Chamber Osculum. Vosmaer (1), in his diagnosis of the Family 

 Spongidae states that their chambers are semi-sperical. This is 

 certainly not the case here, and I take this opportunity to mention 

 that also in several other Australian genera, which, without doubt 

 belong to the SpongidjB as conceived by Vosmaer (I.e.), F. E. 

 Schulze (2) and myself (3) ; the chambers form in a similar way 

 much more than half a, sphere. 



The narrow pores appear very variable in size and number, and 

 I do not doubt that they can be formed in any part of the aboral 

 portion of the ciliated chamber constricted and closed at the option 

 of the sponge. 



The Chamber Osculum (Plate XXIX., fig. 13 0), appeared to 

 me to be clothed by a peculiar flat epithelium. But with such 

 small and delicate structures the observations are of course not 

 very reliable. In the figure (Plate XXIX., fig. 13), I have 

 represented this as it appeared to me. In the A plysillidse, I have 

 found a different arrangement (4), which has also been seen by 

 Vosmaer (5.) Whilst here in Halme, the ciliated cylindrical 

 collar-cell epithelium terminates abruptly, and there is no transition 

 between the high cylindrical elements of the chamber and the flat- 

 cells of the canal epithelium ; we fin d in the cases referred to 

 (Aplysilla, etc.), cells around the inner margin of the Chamber 



(1) (r. C. Vosmaer. Studies on Sponges. I. On Velmfe Gracilis. N. g., 

 n. sp. Mittheilungen aus der Zoologischen Station in Neapel. Band IV., 

 Seite 445. 



(2) F. E. Schulze. Untersuchungen Ueber den Bau und die Entwickehmg 

 der Spongien, VII. , Mittheilung. Zeitschrif t flir wissenschaftliche Zoologie. 

 Band XXXII., Seite 693. 



(3) R- V. Lendenfeld. A Monograph of Australian Sponges. Part II. 

 Proceedings of the Linnean Society of N.S.W., Vol. IX., p. 340. 



(4) R. V. Lendenfeld. Ueber Ccelenteraten der Siidsee, II., Mittheilung 

 Neue Aplysinidae, Zeitschrift fiir wissenschaftliche Zoologie. Band 

 XXXVIII., Seite 260. 



(5) G. C. Vosmaer. Bronn, Classen, und Ordniingen des Thierreiches. 

 Porifera. Seite 182. 



