1 



ER IV 



SILICISPONGIAE— HEXACTINELLIDA 



67 



Lepidospongia Roemer; Leiostracosia, Plectodermatium, Microblastidium Schram- 

 men, etc. Cretaceous. 



Family 5, Ooeloptychidae ZitteL 



Umbel- or mushroom-shaped, with stalk. Wall thin, deeply folded. Convolutions 

 radialhj arranged, hecoming furcate toward periphery of umbel, and exposed on lower 

 surface. Marginal and ^^ 



Upper surface enveloped 

 with porous dermal layer 

 entirely covering thefolds. 

 Ostia only on under side 

 of umbel, situated on 

 backsof thefolds. Frame- 

 work very regulär ; inter- 

 sedion nodes odahedral, 

 perforated ; rays ofhex- 

 actins provided with 

 slender, thorny processes. 



Coeloptychium 

 Goldf. (Fig. 76), oc- 



curring in the Upper Cretaceous of Northern Germany, England, and Southern 

 Russia, is the solitary genus. 



Fig. 77. 

 Flocoscyphia pertusa Gein. I Greensand (Cenomanian) 

 «.'Fragment in\natural size ;l&, Dermal layer, live times enlarged 

 of interior, 12/^1; d, Outward portion of skeleton, 12/j 



Banowitz, Hungary. 

 Skeleton 



Family 6. Maeandrospongidae ZitteL 



Sponge body consisting of thin-walled, intricately labyrinthine, and partially 

 amalgamated tubes or foliae, which form tuberous, pyriform, beaker-shaped, or bush- 



ß like branching Stocks. 



Between the tubes are 

 cavities and interstices 

 of considerable size, 

 which constitute the so- 

 called intercanalicular 

 System. Four canals 

 faintly developed. Der- 

 mal layer absent, or re- 

 presented by a continuous 

 silicious superficial skin. 

 Abundant in the Cre- 

 taceous, and also re- 

 presented by numerous 

 recent genera. 



Flocoscyphia Reuss 

 (Fig. 77). Clump-like 

 or bulbous Stocks con- 

 sisting of labyrinthic, 

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

 small Ostia. Latticed skeleton, intersection nodes solid or perforate. Cre- 

 taceous. 



Becksia Schlüter (Fig. 78). The thin walls of the shallow, beaker-like 



Fig. 78. 



Becksia sokdandi Schlüt. Quadratenkreide ; Coesfeld, Westphalia. A, 

 Sponge body, 1/2 natural size ; 0, Ostia of radial canals ; /, Hollow, root-like 

 processes of wall. B, Skeleton, 50/j. 



