94 POKIFERA. 



Fam. 1. Tetillidse. The characteristic megasclere a protrisene. Tctilla 

 0. Schm. ; Chrotcfla Sollas ; Cinachyra Soil. ; Craniclla 0. Schm. 



Fam. 2. Samidse. Characteristic ruegasclere an amphitritene. tiamus Gray. 



Tribe 2. ASTROPHORA. One or more of the microscleres is an aster. 



Fain. 1. Theneidae. Microscleres are spirasters or amphiasters, and oxyasters 

 or microxeas. Without cortex. Thcnca Gray ; Characella Soil. ; Pcecillastra 

 Soil.; Spliinctrella 0. Schm.; Triptolemus Soil.; Stceba Soil.; Nethea Soil.; 

 Placinastrella F. E. Sch. 



Fam. 2. Pachastrellidae. The chief megascleres are calthrops ; trirenes 

 absent. Microscleres may be spirasters, spherasters, or microrabds. Pachastrella 

 0. Schm. : Drrcitus Gray ; Calthropella Soil. 



Fam. 3. Stellettidae. Euasters always present, but never spirasters or 

 sterrasters. With trifenes; without calthrops. Chamber-system aphodal, and 

 choanosomal mesoderm sarcenchymatous. Megascleres generally arranged on 

 the radiate type. Myriastra Soil. ; Pilochrota Soil. ; Aslrella Soil. ; Anthastra 

 Soil.; Stcllctta 0. Schm.; Draymastra&o\\.\ Aurora Soil. ; Ancorina 0. Schm.; 

 Tribrachium Weltner; Tdhyopsis Stewart; Disyringa Soil.; Stryphnus Soil.; 

 Ecionema Bow.; Papyrula 0. Sclim.; Psammastra Soil.; Algol Soil. 



Fam. 4. Geodiidse. The characteristic microsclere is a sterraster. With 

 trifene megascleres. The sterrasters in the cortex are united together by 

 fusiform fibrillated cells. Erylus Gray; Caminus 0. Schm.; Pachymatisma 

 Bow. ; Cydonium Fleming ; Gcodia Lamarck ; Synops Vos. ; Isops Soil. 



Fam. 5. Placospongidae. The characteristic microsclere is a sterraster. 

 The only megascleres are tylostyles ; trircnes absent. Often placed with the 

 Suberitidce (Monaxonid) on account of tylostyles. Placosponyia Gray. 



Tribe 3. MEGASCLEROPHORA. Without microscleres. 



Fam. Tethyopsillidae. Proteleia R. and D.; Tcthyopsilla Lendf. 



Sub-order 2. IITHISTIDA. 



TctractincUida provided with a consistent skeleton by the zyrjosis of modified 

 spicules or desmas. 



Tribe 1. HOPLOPHORA. With special ectosomal spicules, and usually some 

 form of microsclere. 



A. Ectosomal spicules as tricenes. Aphodal. 



Fam. 1. Tetracladidae. Desma tetracrepid. Tlieonella Gray ; Discodermia 

 Bocage ; llacodiscula Zittel ; Kaliapsis Bow Ncosiphonia Soil. ; Rimella- 

 0. Schm.; Collinetta 0. Schm.; SukastrcUa 0. Schm. 



Fam. 2. Corallistidse. Desma monocrepid (i.e., with crepis as monaxon) 

 and tuberculated. Aphodal. Corallistcs 0. Schm. ; Macandrewia Gray ; 

 Dccdalopclta Soil. ; Hcterophymia Pomel ; Caflipelta Soil. 



Fam. 3. Pleromidae. Desma monocrepid and smooth. Aphodal. Plcroma 

 Soil.; Lyidium 0. Schm. 



B. Ectosomal spicules as microstronyyles or modified microstrongyles (discs). 

 Dcsmas monocrepid. 



Fam. 4. Neopeltidae. Ectosomal spicules as monocrepid discs. Neopclta 

 0. Schm. 



Fam. 5. Scleritodermidae. Ectosomal spicules as microstrongyles and the 

 other microscleres as sigmaspires. Scleritodcrma 0. Schm. ; Aciculitcs 0. Schm. 



Fam. 6. Cladopeltidae. Ectosomal spicules as a monocrepid desma highly 

 branched in a plane parallel to the surface. Microscleres absent. Siphonidium 

 0. Schm. 



