ISO SPONGES 



[Sub-Tribe Eutaxicladixae, Rff.] 



[Family A.stylospoxgidae, Eft".]. *Astijloq)onyia, Roem. [Sil.] ; 

 *Caryospongia, Rff. [Sil.] ; *Car})o»pongia, Rff. [Sil.] ; *Asfylomanon, Roeiu. 

 [Sil.] ; *Caryomanoii, Hinde ; *Palaeomanon, Roem. [Sil.] ; * Protachilleum , 

 Z. [Sil] ; *Eos2)onrjia, Bill [Sil.]. [Family Hindiadae, Rft".]. *Hindia, 

 Duncan [Sil.]. 



Incerti sedis. [Family Rhizomorixa, Z. ( = Corallistidae + Azori- 

 cidae)]. Genera — *C'nemidiastriim, Z. [Jur.] ; *C'oralMdiHm, Z. [Jiir.] ; 

 *Hyalotragos, Z. [Jur.] ; *Pyrgochonia, Z. [Jur.] ; *I)iscostroma, Z. [Jur.] ; 

 *Leiodorella, Z. [Jur.] ; ^Ejnstomella, Z. [Jur.] ; *Platychonia, Z. [Jur.] ; 

 *Bolidium, Z. [Cret.] ; *Astroholia, Z. [Cret.] ; *Chonella, Z. [Cret] ; 

 *Seliscothon, Z. [Cret] ; *Chenendepora, Lamx [Cret.] ; *Verruculina, Z. 

 [Cret] ; *Sticho2)hyma, Pom. [Cret] ; *Jereica, Z. [Cret.] ; *Co('locorypha, 

 Z. [Cret] ; *S(achys2)ongia, Z. [Cret.] ; *Pachinion, Z. [Cret.] ; *NrptereUa, 

 Hinde [Cambr.] ; * Pemmatites, Dun. [Carb.] ; *Kazania, Stuck [Carb.]. 



Grade II. Monaxonida, E. and D. 



Demospongiae Avith monaxon spicules, -without admixture of 

 triaxon or tetraxon types. 



In the classification of this most difficult and perplexing group, 

 which exemplifies in the fullest degree the plasticity of the Demo- 

 spongiae, and the frequency of adaptive and convergent evolution 

 in this class, we follow the classification of Topsent [26 and 28]. 



Order 1. Hadromerina, Topsent 



Monaxonida, u.'sually of nias.sive form, sometimes stalked or cxip-shaped. 

 Structure compact Skeletal framework radiate or without oixier, seldom 

 fibrous, non-reticulate. Spongin absent, or very feebly develoi)ed. Mega- 

 scleres monactinal or diactinal, usually of one kind only ; microscleres, 

 when present, asters or microrhabdi, never chelae or sigmata. 



Sub-Order 1. tAciculina, Tops. 



Mt'^'ascleres diactinal. 



Family 1. Coppatiidae, Tojjs. Microscleres absent, or in the form of 

 euasters, sometimes with the addition of strei:)ta3ters. Spongosorites, 

 Tops. ; Anisonja, Tops. ; Copjmtias, Soil. (incl. Astropeplu:^, SolL ; and 

 Dorypleres, Soil); Magog, Soil.; HcmiastereUa, Crir. ( = £))« //ay, Soil.); 

 Asterojms, Soil. Family 2. Streptasteridae, Tojis. Microscleres strept- 

 asters ; no euastei-s. Genera — Amphius, Soil; Scolvjjes, Soil; Trachy- 

 cladus, Crtr. ; Rhdphidistia, Crtr. ; Spiroxya, Tops. ; Holoxea, To}).s. 

 Family 3. fTETHViDAE, Gray. Globular or massive, with radiating 

 framework and dilferentiated ectosome ; microscleres, when ])resent, 

 typically euasters. Genera — iTethya, Lam. [Eoc], (Fig. 30, A); Tdhyor- 

 rhaphis, Ldf. ; Tuhenllu, Keller (Fig 30, B) ; Truchya, Crtr. ; Hifiro.nju, 

 Tops. Family 4. Stylocoruyliuae, Top.-^. Pedunculate ; framework, 



