ORDER IV 



SIL1CISPOXG1AK HEXACTINELLIDA 



61 



Family 6. Maeandrospongidae. Zittel. 



msistinff of thin-walled, intricate!?/ //>.'/rinthme, and partially 

 amalgamate,/ tub,-* or filling which form tuberous, pyriform, beaker-shaped, or 

 like branching stocks- ! 



tween the </> are cavities 

 mill interstices of consider- 

 able &ize t irliicli coiisfiftitt 

 theso-ntllnl inti'ir.nnnlifii- 

 lar syxfi'iii. /-'"in' canals 

 faintly developed. Dermal 

 t, or represented 

 silicious 



superji''/"/ >////. Almn- 

 < la nt in the Cretaceous, 

 and also represented 

 l>v numerous recent 



FIG. SI. 



Plocost-jn ili in fii'iiuait, (ii-in. Greensand ((Vnonianian); Hanowitz, Hungary. 

 a, Fragment in natural size ; b, Dermal lay.-r, live times enlarged ; c, Sk-l.-tnn 

 of interior, 12/j ; ri, Outward portion of skeleton, 1 2/ 1 . 



genera. 



Plocoscyphia, Reuss. (Fig. 81). Clump-like or bulbous stocks consisting of 



labyrinthic, anastomosing tubes or foliae. Walls of tubes thin, perforated by 



numerous small ostia. Latticed skeleton, intersection nodes solid or perforate. 



Cretaceous. 



Ji'-d-iflu, Schliiter (Fig. 82). The thin walls of the shallow, beaker-like 



sponge are composed of vertical tubes having a radial disposition and fused with 



one another along 

 the sides. Between 

 the tubes are large 

 interstices ; near the 

 base the tubes de- 

 velop hollow, spinous 

 processes. Lattice 

 skeleton very regu- 

 lar, exactly similar 

 to Codoptychium. 

 Upper Cretaceous ; 

 Westphalia. 



Tremabolites, 

 Zitt. ; Etheridgia, 

 Tate ; Zittelispongia, 

 Sinzoff, etc. Upper 



kelandi, Srlilut. C^iadrat.-nkrfide . ( 'u.-st'cld. AV.-st]lialia. 



Camerospongia, 



d'Orb. (Fig. 83). 



(Jlolmlar, sul (-globular, or pyriform. Upper half of the body enveloped by 

 .smooth silicious skin, and with large circular depression on the summit; lower 

 half marked by undulating ridges and furrows, and passing gradually into a 

 stem. Interior of sponge body consists of thin- walled, labyrinthous tubes. 

 Upper Cretaceous. 



Cystispongia, Roem. (Fig. 84). Like the preceding, but with dense silicious 



FIG. 82. 



A, Sponge CretaceOUS. 



l.n.lv. i ., natural six-- ; n, Ostia of radial canals ; /; Hollow, root-like processes of 

 wall. B, Sk.-l.-t.nii, 5J/J. 



