CALCAREOUS SPONGES. 769 



we do not consider that the mere presence or absence of a fovirth 

 ray on a^ radiate spicule in the dermal cortex can be regarded as 

 of generic import. We shall discuss the true characteristics of 

 Leucilla when dealing with that genus. 



The genus Leucandra as now defined may be regarded as 

 derived from a Grantia-W^Q ancestor by the conversion of 

 the syconoid canal system into a leuconoid one, with the 

 simultaneous replacement of the articulate tubar skeleton by 

 an irregularly scattered skeleton of the chamber layer (compare 

 Anamixilla). Indications of the syconoid ancesti-y can, however, 

 frequently be detected in the skeleton (compare Megapogon), 

 while as regards canal system such species as L. australiensis 

 Carter and L. infesta sp. n. (^Leucilla intermedia Row [1909]), 

 which are of the so-called sylleibid type, foi'm connecting links 

 between Grantia and Leucandra. 



We recognise the following sjaecies as belonging to this 

 genus : — 



Section A. With large, usually i-adially arranged oxea, 

 but without microxea. 



1. L, ANANAS Montagu. 



Spo7igia ananas Montagu [1812]. 



Spongia pulvertdenta Grant \\9>2%~], fide Haeckel [1872]. 

 Scij2}ha ovata S. F. Gray [1821],>Ze Haeckel [1872]. 

 Sycimda j»e?wciZZaf«. 0. Schmidt [1870], fide Haeckel 



[1872]. 

 Leucandra ananas Haeckel [1872]. 



2. L. ANGUiNEA Ridley. 



Leucortis anguinea Ridley [1884]. 



3. L. ANOMALA Haeckel. 



Leicceita pandora var. anomala Haeckel [1872]. 



4. L. ARMATA Urban. 



Leuconia armata Urban [1908]. 



5. L. ASPERA 0. Schmidt. 



Sycon asperiom 0. Schmidt [1862], 



'^ Spongia j)c(,nicea Esper [V\,fide Haeckel [1872]. 



'^Spongia infiata Delle Chiaje [1828], fide Haeckel 



[1872]. 

 Leucandra aspera Haeckel [1872]. 



6. L. AUSTRALIENSIS Carter. 



Leaconia fistulosa var. australiensis Carter [1885-1886]. 

 Leucandra australiensis Dendy [1892 B]. 



7. L. CAMiNUS Haeckel. 



Dyssyconella caminus Haeckel [1870]. 

 Leucandra caminus Haeckel [1872]. 



