302 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



are orthotriaenes, and the cloacal triaenes are orthotriaenes with one 

 clad much elongated. There is an ectosomal spheraster, minute. 

 with actines reduced to tubercles; a choanosomal chiaster; also or- 

 thodragmas (trichodragmas). 



The fragments (cloacal tubes), described by Lendenfeld (1906, 

 p. 297) under T. radiella Marshall, present in the matter of the 

 skeleton some close resemblance to T. dubia. There is a dermal 

 crust of strongylasters, but these spicules appear to be true euasters. 

 The chief megascleres of the tube are orthodiaenes (1906, pi. 27, figs. 

 1, 2, 4) of the same type as in the Albatross sponge. The two species 

 differ greatly in respect to the canalar anatomy of the cloacal tube. 

 It is only the tube of T. radiella that is known. 



Family GEODIIDAE. 



Geodiadae Gray, 1867. 

 Geodinidae O. Schmidt, 1S70. 

 Geodiidae Sollas, 1888. — Lendenfeld, 1903. 

 Geodidae Lendenfeld, 1906, p. 305. 



Geodidae plus Erylidae Lendenfeld, 1910; 1910&, p. 267. — Dendy, 1916, pp. 

 254, 256. 



The characteristic microsclere is a sterraster which forms a dense 

 cortical layer. The afferent cortical spaces nearly always, perhaps 

 always, have the character of distinctly differentiated chone canals, 

 which are sometimes uniporal, sometimes cribriporal. Similar 

 efferent chone canals are common, but in their place there are not 

 infrequently present efferent canals of the ordinary tetraxonid type 

 which open by oscula of good size. In a few species the clads of the 

 tetraxon megascleres have degenerated, the triaene thus becoming 

 actually or nearly a tylostyle or style (Geodinella) . Except in 

 Geodinella the tetraxon megascleres are confined to the superficial 

 part of the sponge where they are radially arranged. 



Sollas's (1888) subfamilies Erylina (including Erylus, Ca?ninus, 

 and Pachymatisma) and Geodina (including the remaining genera) 

 were discarded by Lendenfeld, 1903, 1906, who divided the family 

 directly into genera. This seems the better practice. 



In addition to the genera represented in the collection (Eryh's, 

 Geodia, Sidonops, Geodinella) the family includes the following : 



Pachymatisma Bowerbank (1864, p. 171). 



With afferent chone canals the roofs of which are cribriporal. 

 Oscula few, sometimes the apertures of small cloacae; or abundant 

 and scattered; or minute and very numerous. The megasclere- 

 complex includes orthotriaenes and rhabds, but lacks anatriaenes 

 and protriaenes. The sterrasters are spheroidal or ellipsoidal. The 

 other microscleres are microstrong}dcs which form a dermal la} r er, 

 and euasters which do not occur at the surface. 



Lendenfeld (1903, p. 90 would include in this genus the little 

 known SteJletta intermedia O. Schmidt, assigned with a query by 



