444 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



usually separate, but sometimes in groups as trichodragmas; rarely 

 occurring in the shape of the toxa. 



Holotype.— Cat. No. 21326, U.S.N.M. 



In some other species of Clathi'ia, the skeletal framework has dif- 

 ferentiated in the same general direction as in C. fasciculata. Thus 

 Hentschel (1911, p. 364) describes a form (not named) in which the 

 skeleton is made up of spicular bundles which ascend like pillars 

 and between which is suspended, so to speak, a network of delicate 

 horny fibers. And in C. elegantula (Ridley and Dendy, 1887, p. 

 149; Hentschel 1911, p. 372) there are ascending columns between 

 which stretches a reticulum of fibers. But in these forms the col- 

 umns and pillars are not fascicled. 



Family AXINELLIDAE. 



Axiwellidae Ridley and Dendy, 1887, p. 166. 



Sponge body ordinarily more or less upright, of a branching, la- 

 mellate, or cup-like habitus. But massive and even incrusting forms 

 occur, the latter perhaps representing a developmental phase. Skele- 

 ton typically consists of ascending bundles of spiculo-fibers, from 

 which arise subsidiary fibers which radiate to the surface. Skeletal 

 fibers without spined echinating spicules and typically plumose. 

 The characteristic megascleres are monactinal. In addition to 

 these, diactinal megascleres may also occur and in some genera are 

 the only form. Microscleres in the shape of microxeas (to include 

 the acanthoxeas of some forms), trichodragmas, or sigmas occur in a 

 few genera ; cheloid microscleres do not occur. 



Following Dendy (1905, p. 182), certain sponges with axinellid 

 characters but with asters (Vibulinm, for example) have been gen- 

 erally transferred to the Astraxinellidae (in the Hadromerina), al- 

 though Dendy himself now gives up this group. Topsent (1894<?, p. 

 2, 1897; b, p. 249) had already transferred Raspailia to the Ectyoni- 

 nae, a move that has been uniformly followed, Syringella being 

 looked on as a subgenus of Raspailia. Even with these exclusions, 

 Dendy, 1905 (p. 182), regards the family as ill-defined and probably 

 polyphyletic. More recently, 19165, he would delete the family, in- 

 cluding the genera in the Haploscleridae. Still later, 1921&, he 

 would retain the group as a subfamily in the Desmacidonidae. 

 Doubtless there are good phylogenetic arguments underlying these 

 proposed changes, but when one considers how little we know of 

 the ontogeny and the heredity-variation phenomena of sponges, it 

 must be confessed that the value of any considerable change in a 

 generally accepted scheme of classification is at present proble- 

 matical. 



