767 



NEW GENERA OF MONAXONID SPONGES RELATED TO 

 THE GENUS CLATHRIA. 



By E. F. Hallmann, B.Sc, Formerly Linnean Macleay 

 Fellow of the Society in Zoology. 



(Plates xxxvi. — xl., and three Text-figures.) 



The new genera proposed in this paper are Dendrocia, Allo- 

 cia, Isociona, Paracomulum, Megaciella, Tenaciella, Axociella, 

 Isociella, Isopenectya, and Paradoryx. Reference to the last- 

 mentioned, which is for the reception of certain species formerly 

 incorrectly assigned to Clathria, will be found below in my re- 

 marks on the genus Dendrocia; the others are dealt with, each 

 under its own heading, in the order in which they have been 

 enumerated. 



Genus Dendrocia, gen. nov . 



Definition. — Desmacidonidae in which the microscleres are 

 isochelae palmatae (perhaps sometimes accompanied by toxa), 

 the main skeleton is formed of dendritically ramifying spiculo- 

 spongin fibres cored with smooth slender styli (tornostyli) and 

 echinated by small acanthostyli, and the dermal megascleres 

 also are tornostyli, identical in kind with those coring the fibres. 



Type, D. pyramida Lendenfeld (13). 



In addition to the type-species, originally described as Clath- 

 ria pyramida, this genus will include also Clathria alata Dendy. 

 The former is from the coast of New South Wales, the latter 

 from Port Phillip (4) and Western Australia (9). 



The reason for the exclusion of these two species from the 

 genus Clathria I have already indicated in a previous paper (6). 

 Tn all indubitable species of Clathria the styli coring the skele- 

 tal fibres, — the principal styli, — are different in kind from those 

 occurring dermally and interstitially, — the dermal or auxiliary 

 styli. The former spicules are almost invariably more or less 

 curved and gradually tapering (i.e. somewhat conical in shape), 

 whilst the latter, with rare exception, are straight and through- 



