Synopsis of the Australian Calcarea HetevocMa. 71 



the transition from the Sycon to the Leucon type of canal- 

 system has not taken place along a single line of descent, 

 hut along several. Here, as in other cases, we must classify 

 by an assemblage of characters. The canal-system alone is 

 l)y no means sufficient, though, when taken in conjunction 

 with the skeleton, it is often of great value. 



In enumerating the various genera and species I have not 

 attempted to give a complete list of synonyms and references, 

 as this would have taken up a large amount of space. In the 

 case of the species, however, I have given those synonyms 

 and references which are most important. 



My warmest thanks are due to Mr. J. Bracebridge Wilson 

 for the bulk of the specimens here described, to Mr. Thos. 

 Whitelegge for a very valuable collection from Port Jackson,' 

 to the Adelaide Museum for some very interesting specimens 

 from St. Vincent's Gulf, to Professor Spencer foi- a number 

 of specimens from Port Jackson, to Sir Frederick M'Coy for 

 permission to examine the collection in the Melbourne 

 National Museum, and to Dr. Glinther for fragments of type 

 sjiecimens in the British Museum. 



2. Proposed Classification^ of the Calcarea 

 Heteroccela. 



Order HETEROCCELA, Polejaeff. 



Calcareous sponges in which the collared cells are confined 

 to more or less well-defined flagellated chambers. 



Family 1. — Lelx'ascid.e. 



Flagellated chambers very long and nai'row, copiousl}^ 

 branched ; communicating at their proximal ends with 

 exhalant canals which converge towards the oscula ; their 

 blind distal ends covered over by a dermal membrane 

 pierced by true dermal pores which lead into the irregular 

 spaces between the chambers. Skeleton consisting princi- 

 pally of small radiates irregularly scattered in the walls of 

 the chambers and exhalant canals and in the dermal 

 membrane. 



