SPONGES.-HALLMANN. 27c; 



O. tiihulosa, regarded as a species of Ophlitaspongia, seems 

 to me rather divergent. In a number of respects it bears 

 analogies with Siphonochalina bispiculata, Dendy,i and is 

 possibly related thereto. 



Loc. — South-east coast of Australia ("Endeavour"). 



Genus Echinoclathria, Carter. 



External form various; sponge made up of a honey- 

 comb-like mass of anastomosing flattened trabecules. 

 Skeleton — except, perhaps, ivhen foreign particules are 

 included in excessive abundance — a reticidation of fibres 

 usually well provided with spongin. Megascleres of t%vo 

 kinds, distinguishable into principal and auxiliary ; the 

 former are smooth styli, typically occurring in association 

 with the fibres as coring or echinating spicides ; the latter, 

 which vary in form from tylotornota to amphistrongyla, 

 occur inter stitially. Microscleres may be present in the 

 form of palmate isochelce. 



The above, which is an adaptation of the original diagnosis 

 proposed by Ridley and Dendy, is designed so as to secure on 

 the one hand the exclusion from the genus of such species as 

 E. glabra, R. and D., and on the other the admission into it 

 of the species of Lendenfeld's genus Aulena.^ The modifica- 

 tion of the definition in these respects introduces no innova- 

 tion, for Thiele'5 has already expressed the probably correct 

 opinion {vide p. 288) that E. glabra belongs to his genus 

 Echinochalina, and Dendy, ^ by his inclusion in Echinoclathria 

 of a species of Aulena has tacitly rejected the latter genus. 



Speaking of Echinoclathria and Aulena in the sense in 

 which they would be understood if maintained as separate 

 genera, it may be said that although each of the species of 

 Aulena departs in several noteworthy respects from those of 

 Echinoclathria, yet they possess in common no single charac- 

 ter of recognised systematic value by which they may be 

 distinguished from the latter, unless it be their habit of includ- 

 ing foreign particles in the skeleton. In other words, the 

 separation of the two genera depends ultimately upon the 

 presence or absence of extraneous skeletal elements. Similarly, 



1 Dendy— Proc. Eoy. Soc. Vict., vii. (n.s ), 1895, p. 246. 



2 Lendenf eld— Monograph of the Horny Sponges, 1888, p. 91. 



3 Thiele— Kieselschwamme von Ternate, ii., 1903, p. 962. 



4 Dendy— Echinoclathria arenifera, Proc. Roy. Soc. Vict., 1896, p. 40. 



