Synopsis of the Au.sfralian Calcarea Heterocada. 75 



gastral cavity, or main exhalant canals, 1)}^ a more or less 

 complicated canal-system. The skeleton of the chamber 

 layer is irregular. 



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



Genus XI. — Lelapia (Gray, emend.) 



Diagnosis. — Canal ,S3^stem unknown. Skeleton of gastral 

 surface composed of ordinary radiates. Skeleton of dermal 

 surface composed of triradiates, quadriradiates and minute 

 oxea. Skeleton of the chamber layer composed of large, 

 longitudinally arranged oxea, crossed at right angles by 

 bundles of tuning-fork-shaped triradiates whose oral rays 

 are directed towards the gastral cavit}^ while the basals 

 point towards the dermal surface. 



(For species see Part 8 of the present paper). 



Genus ^ll.—Leucyssa, Hreckel. 



Diagnosis. — Flagellated chambers (presumably) spherical 

 or ovoid, irregularly arranged. Skeleton composed solely of 

 oxeote spicules. 



No species of this remarkable genus ai'e as yet recorded 

 from Australian seas, the only examples being Hseckel's 

 Leucyssa spongilla, L. crdacsa and L. incrustans.^ 



Family 4. — HETEROPiD/t:. 



There is a distinct and continuous dermal cortex covering 

 over the chamber laj'er and pierced by inhalant pores. 

 Subdermal sagittal triradiates are present. The flagellated 

 chambers vaiy from elongated and radially arranged to 

 spherical and irregularly^ scatteied. An articulate tubar 

 skeleton may or may not be present. 



Genus XIII. — Grantessa (von Lendenfeld, emend.) 



Diagnosis. — The flagellated chambers are elongated and 

 arranged radially around the central gastral cavity. The 

 dermal cortex consists principally of triradiates and does 

 not contain longitudinally disposed oxea. 



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



* Loc. cit., pp. 137, 138, 139. 



