j^Kvicidacca.'] infcsoeial animaicules. 337 



probablj'^ only a variety of C. radiatas. Fossil in the clialk inaii of 

 Caltanisetta and Oran, and living, in sea water near Cuxliaven. 

 The cells of the discs, from Oran, vary very much in size. Tho 

 granules are of a greenish coloiu- in the living forins, which are very 

 rare. Diameter of fossil l-860th to l-290th ; living, l-580th. 



CosciNODiscus ecccntricus. — Cells small, disposed in eccentric curved 

 lines Found fossil in the chalk marl of Oran, in wliich con- 

 dition, however, it is rare ; but alive, it is met Avith abundantly 

 in sea water near Cuxhaven and Yera Cruz. Locomotion not yet 

 satisfactorily observed. Diameter 1 -860th to 1 -430th. 



C. lineatus. — Cells small, disposed in a series of straight and parel- 

 lel lines. Fossil in the chalk marl of Caltanisetta ; alive at Cuxhaven. 

 The cells in this species form parallel lines in whatever direction 

 tliey may be viewed. In large and well-preserved fossil specimens 

 as many as twent^'-five openings were seen near the circumference. 

 AVithin the live forms, sometimes numerous yellow vesicles are seen, 

 as in GalUonella. Diameter of fossil 1-11 oOth to 1 -480th; living, 

 l-1150th to l-860th. 



C. minor. — Small ; cells small, scattered. Fossil in the chalk 

 marl of Caltanisetta, Oran, and Zante ; and alive in sea water near 

 Cuxhaven. Diameter 1 -11 50th. ^' 



C. Oculus-Iridis. — Cells rather large, radiant ; smaller near the 

 centre and circumference. From five to nine large cells at the 

 centre form a sort of star. Fossil in the chalk marl of Greece, and 

 alive in sea water near Cuxhaven. This large species is curiously 

 marked with coloured rings, which are apparently caused by the 

 peculiar arrangement of the cells. This species differs from C. 

 centralis in having larger cells ; and from C. asteromphalus by its 

 surface being unveiled, and its cells rather smaller. Diameter 

 1- 240th. 



C. limlatus. — Centre cells largest, not radiant ; margin with linear 

 rays, forming a striated rim (limbus). Diameter l-576th. Fossil in 

 Greek marl. The larger cells seven in 1-1 200th. 



C. concavus. — Each valve very concave ; cells large, of equal size ; 

 four and a half in 1-1 200th ; not radiating. An African variety has 

 seven to nine cells in 1- 1200th. Richmond, Vii-ginia. 



