728 PROF. A. DBNDY AND MR. R. W. H. ROW ON 



Genus 2. Dbndya Bidder [1898]. 



Diagnosis. Sponge colony consisting of a large central individual 

 lined by collared cells, from which radially arranged diver- 

 ticula are given off. Skeleton composed of equiangular 

 trira,diates to which quadriradiates may be added. Subgastral • 

 sagittal radiates never present. Nuclei of collared cells 

 probably always basal. 



For illustrations of this genus see Dendy [1891 A]. 



Carter's Clathrina tripodifera was included by Dendy [1891 A] 

 in the genus Leucosolenia, as the sole representative of the 

 "Radiate" section of that genus. Bidder [1898] proposed for 

 its reception a new genus, Denclya, and the recent discovery by 

 the ' Sealark ' Expedition of a closelj' allied, but quite distinct, 

 species in the Indian Ocean seems to justify the retention of 

 Bidder's genus. Unfortunately Bidder associated his genus with 

 PolejaefF's Heteropegma {=: Leucaltis) in a new family Hetero- 

 pegmidse, of which Dendya was made the type genus. While 

 admitting a certain degree of relationship between Dendya and 

 Leucaltis, we cannot agree that this is so close as to justify 

 placing them in the same family, for not only is Leucaltis 

 corticate, while Dendya is non-corticate, but Leucaltis is also 

 heterocoel, while Dendya is homocoel. 



The chief interest attaching to the genus Dendya lies in its 

 radiate structure, which, at first sight, seems to suggest a possible 

 starting point for the Sycettid as well as for the Leucascid- 

 Leucaltid line of descent. We no longer consider, hoAvever, that 

 Dendya stands very near the origin of the Sycettidse, from the 

 simplest of which it difiers widely in the structure of the skeleton, 

 especially in the absence of subgastral sagittal radiates, in the 

 fact that the radial tubes tend to anastomose, and in the basal 

 position of the nuclei of the collared cells. The tendency of the 

 radial tubes to form reticulations is indeed a difiiculty in the way 

 of separating the genus sharply from Jjeucosolenia^ a fact well 

 illustrated by Carter's Leucetta clathrata {=Leii,cosolenia clath- 

 rata), which is intermediate between the two as regai^ds the 

 canal system while resembling Dendya in the presence of the 

 characteristic dermal tripod spicules. [Row, 1913 MS.] 



We recognise the following species as belonging to this 

 genus : — 



1. D. PROLiFERA Dendy. 



Dendya prolif era Dendy [1913]. 



2. D. TRiPODiFERA Carter. Type species of the genus. 



Clathrina tripodifera Carter [1885-1886]. 

 Leucosolenia tripodifera Dendy [1891 A]. 

 Dendya tripodifera Bidder [1898]. 



