M. K. A. Zittel on Fossil LitMstidcc. 329 



Leiodorella, Zitt. 



Planispongia p. p., and Tragos p. p., Quenst. 



Sponge lamellar, ear-shaped, undulated, sometimes nodular 

 or incrusting. Both surfaces coated with a smooth, apparently- 

 dense covering-layer, from which project scattered, margined, 

 round oscula. From these, short, somewhat bent canals, 

 branched at the end, penetrate perpendicularly into the wall. 



Sketeton consisting of a rather dense complication of 

 branched lithistid corpuscles with short, simple axial canal, 

 and their short thick branches furnished with a moderate 

 number of pointed processes. Surface-layer formed of small 

 ])ronged and branched corpuscles. 



In its external appearance this genus represents the Creta- 

 ceous genus Amphithelion^ just as Epistomella may be regarded 

 as the Jurassic precursor of Verruculina. Both the Jurassic 

 genera agree in their skeletal elements with Hyalotragos^ Cne- 

 midiastruniy and Platychonia^ while the Cretaceous genera have 

 much thinner corpuscles furnished all over with nodular or 

 root-like processes. The axial canals of the former are short 

 and fine, while those of Verruculina and Amphithelion are of 

 considerable diameter, traverse the whole main stem, and 

 sometimes run into the branches. Only known from the 

 Upper Jura. Species : — 



1. Leiodorella expansa^ Zitt. Lobate or ear-shaped, forming- 

 rath er thick leaves ; margin rounded off. Oscula bordered, 

 verruciform, scattered. Zone of Amm. transversariits,Wodna,y 

 near Cracow. 



2. Tragos tuhatum, Quenst. Petr. cxxix. 19. 



Also several other species from the White Jura of Switzer- 

 land, Swabia, Franconia, and the Cracow district. 



Epistomella, Zitt. 



Planispongia p. p., and Spongites p. p., Quenst. 



Sponge ear-shaped or lamellar, laterally stalked. Upper 

 surface with scattered, margined, round oscula ; under surface 

 with pores. Stomachal cavities of the oscula moderately deep. 

 Skeleton and canal-system as in Leiodorella. Rare in the 

 Upper Jm*a. 



1. Epistomella clivosa^ Quenst. Petr. cxxxi. 4, 5. 

 Platychonia, Zitt. 



Spongites p. p., and Planispongia p. p., Quenst. 

 Amorphospongia p.p., D'Orb. 

 ? PlocociJelia, Etal. 



Sponge lamellar, car-shaped, undulated, folded, rarely cup- 



