504 M. K. A. Zittel on Fossil Hexactinellida. 



scarcely developed ; ostia very small, irregularly distributed. 

 Surface naked. Skeleton as in Sporadopyle. Axial canals 

 of the sexradiates wide. 



^ScypMa verrucosa^ Goldf. Taf. xxxviii. 8 a-d. 



8. (jregaria, Quenst. Jura, Taf. 81. 80. 

 ^Polycoelia Icevigata, F. A. liom. Spongit. taf. xi. 8. 



Family 3. Coscinoporidge. 



? BOTHEOCONIS, Kingf. 

 Monogi'. of Permian Fossils, Pal. Soc. 1849, p. 14. 



Leptopheagma, Zitt. 



Sponge-body cup-sliaped. Wall thin. Both surfaces with 

 numerous small ostia of very fine csecal radial canals, gene- 

 rally arranged in longitudinal and transverse rows. Skeleton 

 stony, consisting of a dense latticed tissue of rather irregular 

 arrangement. The meshes between the siliceous fibres are of 

 very various forins. Crossing-nodes of the sexradiates solid. 

 Structure of the root agreeing with that of the wall. 



^^cypliia MiircMsonii^ Goldf. Taf. Ixv. 8. 

 ^S". striato'punctata^ Rom. Kr. 3. 7. 

 8. angular is, Rom. Kr. 3. 2. 

 8.jragiLiSj Rom. Kr. 3. 11. 



Pleueostoma, Rom (p.p.). 



Nordd. Kr. p. 5, 



Sponge-body laminar and cup-shaped or branched, always 

 strongly compressed, with a series of large apertures on the 

 rounded narrow surfaces. Wall thin, on both sides witli 

 numerous, irregularly arranged, small ostia. Radial canals 

 simple, blind. Skeletal structure as in the preceding genus. 



Pleurostoma radiatum^ Rom. Kr. 1. 11 \. 

 P. hohemicurrij Zitt., n. sp. 



GUETTAEDIA, Mich. 



Iconogr. Zoophyt. p. 121. 

 Sponge-body stellately folded. The three to eight folds of 



t The position of this genus is very doubtful. According to the figure 

 (Perm. Foss. pi. ii. fig. 7 a) it appears to belong to the Hexactmellida. 

 Still more problematical is Co7iis, Lonsd. (Quart. Journ. Geol. Soc. v. 

 pp. 55-Go), from Atherfield, which possibly possessed a calcareous skele- 

 ton, 



X Pleurostoma lacunosmn, Rom., belongs to the family Callodictyonidpe, 

 and is the typical species of the genus Pleurope, 



