72 Proceedin(/s of the Royal SGciety of Victoria. 



Genus I. — Leiica^cun, nov. g-en. 

 Diagnosis. — The same as that of the family. 

 (For species see Part 3 of the present paper.) 



Family -1. — Sycettid^. 



Flagellated chambers elongated, ai-ranged radially around 

 a central gastral cavity, their distal ends pn^jecting more or 

 less on the dermal surface and not covered over by a con- 

 tinuous cortex. Skeleton radially S3aiimetrical. 



Genus II. — Sijcdta (Hieckel, emend.) 



Diagnosis. — Radial chambers not inter-commuuicating. 

 Articulate tubar skeleton. No tufts of oxea on the distal 

 ends of the chambers. 



(For example see Part 3 of the present ])aper.) 



Genus III. — Sycon (Risso, emend.) 



Diagnosis. — Radial chambers not inter-communicating. 

 Articulate tubar skeleton. The distal ends of the chambers 

 provided each with a tuft of oxeote spicules. 



(For examples see Part 3 of the present paper.) 



Genus IV. — Sycaiifha, von Lendenfeld. 



Radial chambers long, united in groups ; those of each 

 group inter-communicating by openings in their walls and 

 each group with a single common opening into the gastral 

 cavity. The radial chambers have freel}' projecting distal 

 cones surmounted by oxeote spicule.s. Tubar skeleton 

 articulate. 



No Australian species of this genus has yet l)een found. 

 The t3qoe is von Lendenfeld's SycantJiu tenella.* 



Family 3. — Grantid.e. 



There is a distinct and continuous dermal cortex covering 

 over the chamber layer and pierced by inhalant pores. 



* " Die Spougien cler Aclria. I. Die Kalliscliwiimme," p. 51. 



