108 F r i e d r i c h D r e y e r , 



the breadth of each riug. Osculum three times as broad as the 

 central chamber, surrounded by a crown of strong conical teeth. 



Dimensions. — Length of the disk 0,18; breadth 0,16; breadth 

 of each ring and of the central chamber 0,02; pores 0,003. 



Habitat. — Fossil in Tertiary rocks of Sicily, Grotte (Stohr), 

 Caltanisetta (Haeckel). 



6. Ommatodiscus laevigatus, Stohr. 

 Ominatodiscus laevigatus, Stohr, 1880. loc. cit. Taf. VI, figs. 9, 9a. 



Disk elliptical (3 : 4), with three chambered rings around the 

 circular central chamber, the third ring half as broad as the se- 

 cond. Chambers twice as high as broad. Pores very small, one- 

 third as broad as the bars. Osculum twice as broad as the cen- 

 tral chamber, armed with a crown of short conical teeth. 



Dimensions. — Length of the disk 0,15; breadth 0,11 ; breadth 

 of inner rings 0,02; of the outer 0,01; pores 0,0017. 



Habitat. — Fossil in Tertiary rocks of Sicily, Grotte (Stohr). 

 AuCerdem fand ich diese Art in der Bodenprobe von Station 271. 



7. Ommatodiscus fragilis, Stohr. 

 Ommatodiscus fragilis, Stohr, 1880, loc. cit. Taf. VI, figs. 10, 10a. 



Disk elliptical (4 : 5), with five chambered rings around the 

 elliptical central chamber, the fifth ring twice as broad as each 

 of the others. Chambers about as high as broad. Pores very 

 small, one-fifth as broad as the bars. Osculum three times as 

 broad as the central chamber, surrounded by a coronet of short 

 teeth. 



Dimensions. — Length of the disk 0,17 ; breadth 0,13; breadth 

 of the inner rings 0,01; of the outer 0,02; pores 0,001. 



Habitat. — Fossil in Tertiary rocks of Sicily and Barbados; 

 living in depths of the Tropical Atlantic and Pacific, Station 353, 

 depth 2965 fathoms; Station 265, depth 2900 fathoms, etc. 



8. Ommatodiscus amphiacanthus, nov. spec. Fig. 57. 

 Die Scheibe ist regelmafiig elliptisch , das Ringbalkensystem 

 ist, abgesehen von der kleinen kreisrunden Zentralkammer, wie es 

 scheint , schon auf dem Wege zur Degeneration begriffen ; auBer 

 der Zentralkammer sind 2 Ringbalken vorhanden, dieselben sind 

 von unregelmaBig elliptischer Form und an einigen Stellen unter- 

 brochen. Auch die Radialbalken sind unregelmaBig verteilt und 

 tcilweise nur fragmentarisch vorhanden. Die Schalenoberflache ist 



