386 M. K. A. Zittel on Fossil LitMstidce. 



pyriform, or obconical, shortly stalked, attached by a broad 

 disciform foot. Vertex truncate or with a shallow pit, in 

 which are the apertures of several round efferent tubes which 

 vertically traverse the whole sponge-body. Surface uniformly 

 covered with pores, from which capillary radial canals pene- 

 trate to the centre of the sj)onge. Skeleton composed of fine, 

 radiciform, irregularly branched or simple siliceous corpuscles, 

 elegantly filigreedby numerous longer and shorter side branches; 

 they lie close together, and are united into radial trains by 

 their processes. In some species {J. punctata) the radial 

 canals are in vertical rows ; the walls of these are formed by 

 the interlaced branched ends of the corpuscles, the main stems 

 of Avhich form pillars uniting two neighbouring lamella3. 



This genus closely resembles Jerea outwardly ; but the 

 microstructure is quite different. In Jerea the skeletal ele- 

 ments are more or less regular quadriradiates of considerable 

 size, which form a loose meshed texture. Externally Jereica 

 differs from Jerea by the finer and more uniform pores of the 

 surface, the absence of a branched base, and the very nume- 

 rous radial canals. 



The typical species are : — 



*1. Jerea 'polystoma^ Rom. Spong. xii. 5. Senonian, 

 Ahlten. 

 *2. Jerea tuherculata, Rom. ib. xiii. 3. Senonian, Ahlten. 



3. Jerea 2)unctataj Goldf. Ixv. 13. Senonian, Sutmerberg. 

 Sjnanisjionffia pmictafa, Queust. Petr. cxxxiv. 10-12. 



4. Jerea sexplicata, Rom. Spong. xii. 4. Senonian. 



5. Sj^umispongia alveare^ Quenst. Petr. cxxxiv. 20. Seno- 

 nian, Ilsenburg. 



Also probably Jerea ocellnta^ oligostoma^ tessellata^ and ma- 

 millosa^ Rom., from the Cretaceous of Ilsenburg. 



Very likely many of the sponges from the Miocene of Oran 

 described by Pome! under the genera Jerea^ Jereopsis, Ischa' 

 dm) Polyjerea, and Dichojerea belong to Jereica. 



CCELOCORYPHA, Zitt. 



Scyphia p. p., Siphonia p. p., JSudea p. p., and Siphonocoelia p. p., F. A. 



Rom. 

 iSpu7)nsponffia p. p., Quenst. 



Sponge simple or compound, with a broad base, or cylindri- 

 cal. Vertex convex, with a tubular stomachal cavity, which 

 is sometimes shallow, sometimes more or less deep. Fre- 

 quently radiating, branched, superficial furrows run from its 

 upper margin. Sides uniformly covered with numerous pores, 

 opening into fine radial canals. Skeleton composed of small 



