CALCAREOUS SPONGES. 78 S 



Genus 47. Syculmis Haeckel [1872] (emend.). 



Diagnosis. Canal system syconoid. With a i^oot-tuft of oxea and 

 anchoring quadriradiates. 



For illusti-ations of this genus see Haeckel [1872]. 



This is a highly specialised genus of a single species, but had it 

 not already been proposed by Haeckel, we should hardly have felt 

 justified in distinguishing a special genus on the characters, 

 available. 



The only known species is : — 



1. S. STNAPTA Haeckel. 



Syculmis synapta Haeckel [1872]. 



Genus 48. Leucilla Haeckel 1872 (emend.). 



Diagnosis. Canal system sylleibid or leuconoid. Skeleton of the 

 chamber layer typically composed of the centripetally and 

 centrifugally directed apical rays of subdermal and sub- 

 gastral quadriradiates, but subgastral sagittal triradiates and 

 confused chamber-layer quadriradiates may be present, while 

 the subgastral quadriradiates may be absent. 



For illustrations of this genus see Haeckel [1872] and Dendy 



[1893A]. 



The resemblance of this genus to some species of Leucandra 

 has already been pointed out. It also resembles by convergence 

 some species of the genus Leucetta, but may be distinguished by 

 the fact that traces of syconoid ancestry are still to be met with 

 in the skeleton (e. g., the presence in some species of subgastral 

 sagittal triradiates), while the triradiates are not of the cha- 

 racteristic regular tyjoe occuri-ing in the Leucascidse. The position 

 of the nucleus of the collared cells, as detei-mined in Leucilla 

 australiensis and L. princeps, is, moreover, ap)ical, instead of 

 basal as in the Leucascidpe. 



We recognise the following species as belonging to this 

 genus : — 



Section A. Without oxea. 



1. L. AMPHORA Haeckel. Type species of the genus. 



Leucilla amphora Haeckel [1872]. 



2. L. AUSTRALIENSIS Carter. 



Leuconia johnstonii var. australiensis Carter [1885-1886]. 

 Leucilla australiensis Dendy [1892 B]. 



