520 Rijvlsioisf of the axinellid^, ii., 



foreign skeletal elements are broken spicules. Sty loir ichoph ova 

 was placed by Dendy in the family Haploscleridfe (Heteror- 

 rhapliidte),in vicinity to Phoriospongia Marshall, and (J hond7-opsis 

 Carter, but for reasons which I intend to publish in a subsequent 

 paper, it appears to me rather that these genera are degraded 

 Desraacidonidse, requiring at present to be included in the sub- 

 family Mycalinie. 



SiGMAXiNELLA Dendy (emeiid.). 



Definition. — Axinellidte of ramose habit, with cylindrical or 

 compressed branches, and witlioutconuli or otlierkind of surface- 

 processes. Skeleton syminetrically arranged, consisting axially 

 of a more or less condensed or core-like region formed bv a 

 reticulation of spongin-ensheathed spicule fibres : extra axial 

 skeleton consisting of paucispicular main fibres radiating out- 

 wards to the surface, sometimes (when of considerable length) 

 connected by frequent, typically aspiculous, transverse fibies, 

 but more usually with relatively few, or altogether without, 

 transverse connections. Megascleres typically of a single oider: 

 styli, sometimes in part transformed into oxea or strongjla. 

 Microscleres : sigmata and trichites (or microxea), the latter 

 either in dragmata or scattered singly. 



Type, S. (lustraliana Dendy. 



As amended, the genus will include only three of the species 

 which have formerly been assigned to it. Of the remaining 

 four, S. ciocalyptoidett Dendy, and S. iiicruiytaits Kirkpatrick, are 

 transferred to liiemiia; S. Jiabellata (Carter), redescribed below, 

 is made the type of a new genus, Sigmaxio, while S. vianimillata 

 \Vhitelegge(60), with its rhabdostylote megascleres (which are 

 found to show traces of spination, and are accompanied by 

 sigmata only), possesses a type of spiculation veiy similar to that 

 of Carter's i/ic?06-io?ia intexta,— 'A species referred Avith liesita- 

 tion by Topsent(53) to his genus Bhahderemia,- and requires for 

 its reception a new genus, to be included in the Myxillina^, for 

 which I propose the name lihahdostyma. On the other hand, 

 two species are now added to the genus,— one new, the other 

 long since described by Carter under the name Fhakellia ramosa. 



