354 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



Thiele, 1900 (pp. 64-65), pointed out the similarities of the 

 Chondrosidae to Donatio, (Tethya at that time). He regards the 

 family as derived through reduction from Donatia-Wko, forms and 

 puts it in the Clavulida (=Hadromerina part). Dendy, 1905 (pp. 

 107, 130), follows Thiele in ranging the family under the Hadro- 

 merina (Astromonaxonellida Dendy) as forms, not primitively 

 simple like the Myxospongida, but in which the megascleres have 

 been lost and in some species the microscleres also. 



Hentschel 1909, 1912, likewise places the Chondrosidae along with 

 the Donatiidae. Like Dendy, in the latters more recent papers, he 

 does not separate the groups Astrophora and Hadromerina 

 (Astromonaxonellida) . 



Dendy, 1916 (p. 267), would include in the family only Chon- 

 drilla and Ghondrosia. He derives the family and the Donatiidae 

 from the Stellettidae, ranging it as one of the astrotetraxonid fami- 

 lies which, as said, he does not separate into tetractinellid and 

 monaxonid groups. 



Family ASTRAXINELLIDAE. 



Astraxinellidae Dendy, 1905. 



Dendy, 1905 (p. 107), suggested that certain forms such as Vib- 

 ulinus Gray, 1867, which owing to habitus and the anatomy of 

 the skeleton in general have been referred to the Axinellidae, should 

 be grouped owing to the possession of astrose microscleres in a new 

 family, the Astraxinellidae, of the Hadromerina (Astromonaxonel- 

 lida). Stephens (1912, p. 59; 19156, p. 28) has followed this sug- 

 gestion. 



In this family fall also Adreus Gray, 1867, and II emimtrella 

 Carter, 1879. Topsent, 1919, reviews the latter genus, merging in 

 it not only Epallax Sollas, 1888 but Kalastrella Kirkpatrick, 1903. 

 Topsent would place it in the Axinellidae alongside of Adreus and 

 Vibulinus. Hallman (1912, p. 132) adds to the Astraxinellidae 

 his new genus Paracordyla. Dendy (19216, p. 107) in his most 

 recent memoir would abandon the family on the ground that the 

 astrose microscleres may be regarded as degenerate acanthostyles. 

 and the genera possessing them may thus be gathered under the 

 Ectyoninae. 



(Family Spirasigmidae. A new family has been suggested by 

 Hallman, 1912 (p. 131, footnote), under this name for certain de- 

 scribed forms: Trachygellius {Trachya) globosa Carter, Spirasigma, 

 new genus for Gellius aculeatus Whitelegge, and possibly Trachy- 

 cladus Carter usually classed in the Epipolasidae.) 



