M. K. A. Zittel on Fossil Lithistidce. 239 



B. Skeletal corpuscles strongly branched, with a rather 

 wide ramified canal, often interlocked to form fibre-like 

 trains. 



a. Sponge-body nodular or branched, without a distinct 

 canal-sjstem. Surface with scattered oscula, which are some- 

 times pit-like, sometimes radiate, or sometimes only with fine 

 pores. 



Bolidimn, Zitt. (Cretaceous). Nodiilar or branched, without oscuhi. 

 Astrobolia, Zitt. (Cretaceous). Nodular, with scattered, radiate or large 

 pit-like oscula. 



h. Sponge-body basin-shaped, cup-sliaped, ear-shaped, or 

 laminiform. Wall with oscula or pores on one or both sur- 

 faces ; from these simple or slightly ramified and generally 

 curved canals penetrate perpendicularly into the wall, but do 

 not traverse it. Surface-spicules, when present, like the skele- 

 tal elements, or forked anchors, sometimes also anchors with 

 recurved prongs. Uniaxial spicules are also generally present 

 in abundance. 



Chonella, Zitt. (Cretaceous). Cup- or basin-shaped ; both surfaces fur- 

 nished with pores. 



^^eliscothon, Zitt. (Cretaceous), Basin-, cup-, or plate-shaped ; wall 

 consisting of vertical laminfe ; on the radial canals of the inner sur- 

 face there are small oscida. 



Chenendopuru, Lamx. (Cretaceous). Cup-shaped, stalked, with a branched 

 root ; inner surface with scattered impressed oscula ; stem with ver- 

 tical tubes ; skeletal corpuscles rather large, knobby. 



Arabescula, Cart. (Recent). Thin, incrusting ; surface with pores and 

 fine furrows. 



Corallistes, Schm, (Recent). Cup- or ba,sin-shaped, or curved discoid; 

 oscula on the inner surface ; surface covered with a coat of forked 

 anchors. 



Ileterophyniia^ Pom. (Recent). Fan-shaped, imdidately folded; upper 

 sm'face Avith oscula ; imder surface porous. Surface-spicules of the 

 under sm-face curved anchors with short incrassate prongs ; of 

 the upper surface smooth, irregidarly branched corpuscles of small 

 size. 



3Iacandreioia, Gray (Recent). Vas&-shaped or clavate. Inner surface 

 with warty oscula. Surface-spicules consisting of a short shaft and 

 three branched, finely divided, and curved arms. Flesh-spicules uni- 

 axial, pointed at both ends. 



Azorica, Cart. (Recent). Vase-shaped, stalked. Warty oscula on the 

 inner surface. Skeletal corpuscles small. Main branches smooth, 

 strongly branched at the ends. Surface -structures resembling the 

 skeletal elements. 



LeioderMaiium, Schm. (Recent). Like Azorica, but the prominent 

 oscula on the outside. 



VerrneuUna, Zitt. (Cretaceous). Basin-, cup-, or ear- shaped or lamini- 

 form. Inner (upper) surface witli prominent warty oscida. Sur- 

 face-elements like those of the skeleton. 



AnipJiilhelioii, Zitt, (Jura, Cretaceous). Tjike VcyrucHliiKi, hut witli 

 ■\\artv oscula on both surfaces. 



