SILICIOUS AND HORNY SPONGES WILSON. 351 



Family SUBERITIDAE. 



Suberitidvnae part O. Schmidt, 1870, p. 46. 



Suberitidac part Vosmaer, 18S7, p. 330. — Part Ridley and Dendy, 1887, p. 

 197.— Plus Mesapidae Topsent, 1898, pp. 103, 104. 



Without a differentiated cortex. Skeleton either not radiate or 

 radiate only in a partial way. Megascleres tylostyles or styles. 

 Microscleres absent or represented in some forms by rhabds (centro- 

 tylote microstrongyles, or spinose rhabds that are tylostyles or 

 variants of such). 



In addition to Rhizaxinella (see below) the genera are Suberites 

 Nardo, 1833. Ficulina Gray, 1868, Laxosuberites Topsent, 1896, 

 Terpios Duchassaing and Michelotti, 1864 (see Dendy 19216, p. 

 148), Pseudosuberites Topsent, 1896 (syn. Suberanthus Lendenfeld), 

 Prosuberites Topsent, 1893, AxosubeHtes Topsent, 1893, Mesapos 

 Gray, 1867, and Tethyspira Topsent, 1890. For the latter two gen- 

 era Topsent erected (1898) a special family, Mesapidae, retained in 

 1900 (p. 252) and 1904 (p. 19). Topsent in 1919 removes Semisuber- 

 ites Carter, 1877 (syn. Cribrochalina O. Schmidt in the sense of 

 Vosmaer 1882, 1885; syn. Plectodendron Lendenfeld), transferring 

 it to the Desmacidonidae. 



Thiele (1898, 1905) discusses the genus Suberites. He thinks 

 Topsent's genera Pseudosuberites , Laxosuberites, and Prosuberites 

 should have the value of subgenera. Terpios and Ficulina should 

 also, he thinks, be classed as subgenera; a new subgenus, Suberella, 

 should be made for Suberites heros O. Schmidt, and Suberites sens. 

 str. be reserved for forms like S. domuncula (Olivi). 



Dendy, 1905, (p. 130), uses Suberites in a comprehensive sense, 

 although he partly indorses Topsent's splitting of the genus into 

 Pseudosuberites, etc. 



Genus RHIZAXINELLA Keller (1880). 



Rhizaxinella Keller, 1880. p. 272. — Topsent, 1898, p. 104. 



Pedunculate forms, the peduncle sometimes branched, each branch 

 ending above in a body. Body spherical, ovoid, or cylindrical, with 

 an osculum near the summit; stalk attached to substratum by a 

 plate-like expansion or a set of roots. Megascleres are tylostyles 

 or styles; among them, in several species, sinuously curved forms. 

 Spicules of the body more or less radiately arranged. Peduncle 

 includes, or in the adult state of some species consists of, a dense 

 bundle of longitudinally arranged spicules. 



The genus shades over into Suberites. (See Thiele's discussion, 

 1898.) There is an interesting resemblance, especially of certain 



