326 BULLETIN" 100, UNITED STATES NATIONAL MUSEUM. 



Suborder Hadromerina. 



Hadromcrina Topsent, 189S plus. 



Sponge body generally compact and massive, approaching a defi- 

 nite shape, sometimes lamellate; also incrusting. Megascleres all 

 monaxonid, often radially or somewhat radially arranged. In a 

 few forms (Chondrosidae) the megascleres have been lost. Skele- 

 ton rarely fibrous, not distinctly reticulate, and usually without 

 spongin. Microscleres, if present, are asters of some form, includ- 

 ing under this term astrose spicules which develop from monaxon 

 primordia with which chelae are associated in a few species. Prob- 

 ably derived for the most part from the Astrophora through loss of 

 the tetractinellid megascleres but possibly polyphyletic. 



Thiele (1898) and Dendy (1905, p. 106) pointed out that Topsent 's 

 sections, Aciculida and Clavulida, could not be retained since the 

 characteristic megasclere in some of the Aciculida was in reality 

 monactinal and not diactinal. In Donatio,, for example, and in 

 Tuberella, the so-called strongyloxea does not differ from a style. 

 The sections are therefore abandoned and the group is divided at 

 once into families. 



For definitions and synonymy of the genera, in general, Topsent, 

 1898, is of the first importance. For the earlier history of many 

 genera Vosmaer, 1887, is indispensable. Dendy, 19216, lays em- 

 phasis on the distinction between true asters (euasters) and " pseud- 

 asters " (microscleres which develop from monaxon primordia) and 

 transfers several families (Spirastrellidae, Clionidae, Suberitidae, 

 Polymastidae) to the immediate neighborhood of the Desmacidon- 

 idae, which he would regard as the parent family. (See Spirastrel- 

 lidae). He further restricts the group by deleting the Epipolasidae, 

 referring these genera largely to the Stellettidae (1916, pp. 225, 235; 

 19166, p. 93). 



I have not been able to consult the original and so do not attempt 

 to distribute Kowalewskyella and Protosuberites, new genera by 

 Svarchevskii. (See Zoological Record for 1905.) 



Family EPIPOLASIDAE. 



Epipolasidae Sollas, 18S8. 



Coppatiidae Topsent, 1S98, p. 108 plus Streptastcridae Topsent, 189S, p. 109. 



With oxeate magascleres and typically with 'astrose microscleres, 

 but the latter may be lost (Spongosoritcs, Topsentia). The asters 

 may be all euasters or euasters associated with sanidasters (Aster- 

 opus) or all streptasters (inclusive of sanidasters), with which 

 microrhabds or trichodragmas may be associated. 



Dendy (1905, p. 107) combined Topsent's two families, and has 

 been followed by Hentschel (1909. 1912) and Stephens (19156). 



