76 Proceedings of the Royal Society of Victoria. 



Genus XIV. — Heteropia (Carter, emend.) 



Diagnosis. — The distal ends of the elongated radial 

 chambers are covered over by a well-developed dermal 

 cortex, consisting principally of large oxea arranged parallel 

 to the long axis of the sponge. 



I propose to retain this generic name for Carter's Apltvo- 

 ceras raniosa,* which he observes belongs to his genus 

 Heteroina. No species are yet known from Australia. 



Genus XV. — Vosmaerop.sis, nov. gen. 



Diagnosis. — Flagellated chambers spherical or sac-shaped, 

 never truly radial. Dermal cortex composed principally of 

 triradiates, without longitudinally disposed oxea. 



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



Family 5. — Amphoriscid^. 



There is a distinct and continuous dermal cortex covering- 

 over the chamber layer. Subdermal quadrii-adiates are pre- 

 sent. The flagellated chambers var}^ from elongated and 

 radially arranged to spherical and irregularly scattered. 



Genus XVI. — Heteropegma (PolejaefF, emend.) 



Diagnosis. — The flagellated chambers are elongated and 

 arranged radially around the cential gastral cavity. There 

 is a vestigial tubar skeleton of minute radiates. The dermal 

 coi'tex is very thick, composed principall}' of large triradiate 

 spicules. 



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



Genus XVII. — Amphoriscus (Hreckel, emend.) 



Diagnosis. — The flagellated chambers are elongated and 

 arranged radially around the central gastral cavity. The 

 skeleton of the chamber layer is composed exclusively of the 

 apical rays of subdermal and subgastral quadriradiates. 



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



Genus XVIII. — Sycidmis (H?eckel, emend) 



Diagnosis. — The flagellated chambers are elongated and 

 ari-anged radially around the central gastral cavity. The 



* Proc. Lit. PhiL Soc. Liverpool, VoL XL, Appeudi-N:, 1886, p. 92. 



