St/uopsis of the Australian Calcarea Heterocoda. 73 



There are no subderraal sagittal triradiafces or quadriradiates.* 

 The flagellated chambers vary from elongated and radially 

 arranged to spherical and irregularly scattered, while the 

 skeleton of the chamber layer varies from regularly articulate 

 to irregularly scattered. 



Genus V. — Grant ia (Fleming, eraend.) 



Diagnosis. — The elongated flagellated chambers are ar- 

 ranged radially around the central gastral cavity ; they are 

 not provided with tutts of oxea at their distal ends, but are 

 covered over by a dermal cortex composed ])rincipally of 

 triradiate spicules and without longitudinally disposed oxea. 

 An articulate tubar skeleton is presents 



(For examples see Pai-t 3 of the present paper.) 



S lib-Gen us. — Gra nt iops is, no v. 



Diagnosis. — The sponge has the form of a greatly elongated, 

 hollow tube, whose wall is composed of two distinct layers 

 of about equal thickness. The outer (cortical) layer is 

 provided with a very strongly developed skeleton of radiate 

 spicules and contains the narrow, ramif}dng inhalant canals. 

 The inner (chamber) layer is formed b}^ elongated I'adial 

 chamljers arranged very regularly side by side. The 

 skeleton of the chamber layer is very feebly developed ; the 

 normal subgastral triradiates ai-e replaced by quadiiradiates ; 

 the tubar skeleton is articulate, and composed of very 

 abnormal sagittal triradiates whose ])aired rays are greatl}^ 

 reduced. 



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



Genus VI. — Ute (Schmidt, emend.) 



Diagnosis. — The ends of the elongated radial chambers 

 are covered over by a well developed cortex, consisting in 

 great part of large oxeote spicules arranged parallel to the 

 long axis of the sponge. Tlie tubar skeleton is articulate 

 or else composed entirely of the basal rays of subgastral 

 triradiates. 



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



* I propose these names for spicules lying beneath the dermal surface and 

 with inwardly directed basal or apical rays as the case may be. Such 

 spicules are of great importance for purposes of classification. 



