Dr. J. E. Gray on the Classification of Sponges. 451 



long subulate ends, and witli scattered spheres of very long- 

 radiating spicules with dilated ends. 



Lanuginella^ Kent, Microsc. Journ. 1870, tab. Ixv. 



Sect. 2. Hexaradiate spines in the sarcode. 



A. Sponge free^ attached to the mud hy numerous elongated 

 filamentous spicules surrounding its base and having 

 small recurved spines at the end. Skeleton formed of 

 elongated cylindrical spicules more or less united hy sili- 

 ceous secretion. 



Fam. 3. Euplectelladae. 



Sponge tubular, free, formed of bundles of elongated thread- 

 like spicules placed in horizontal transverse and oblique direc- 

 tions, often crossing each other, forming more or less irregular 

 network, and often closed at the top by a netted lid formed 

 of shorter spicules ; the base with elongated free spicules 

 terminating in three or four short spines, by which it is fixed 

 to the mud. The sarcode mucilaginous, studded with dif- 

 ferently shaped spines, some of which are many-rayed, stellate, 

 with clavate arms. 



Euplectelladai, sect. A, Gray, P. Z. S. 1867, p. 528. 

 Euplectella. 



Fam. 4. Hyalothaumadae. 



Sponge elongate, free, wider above, with anchoring fibres at 

 the base. The filiform spicules united into bundles, which 

 anastomose freely with each other, forming a solid framework. 



Hyalothauma, Herklots and Marshall ; ? Semperella^ Gray, 

 Ann. & Mag. N. H. 1868, xi. p. 373 ; Eureta, Semper. 



B. Sponge fixed ; spicules united together hy siliceous matter^ 



forming a netted mass covered with sarcode^ in which 

 are scattered other dijferently shaped spicules. Spicules 

 of skeleton forming a coral-like mass. 



COEALLIOSPONGIA, Gray, P. Z. S. 1867, p. 505 ; Ann. & 

 Mag. Nat. Hist. 1868, i. p. 165. 



These sponges are hard and coral-like, the skeleton being 

 formed of siliceous spicules anchylosed together, forming a 

 hard siliceous mass, covei-ed with sarcode. They contain a 

 number of very curiously shaped spicules, which are generally 

 free, of very different forms in the different genera : some 

 have regular spines with three-spined ends, like Tethya and 

 Geodia^ which are sometimes bifid and forked at the end, 



