312 DESCRIPTION OF {^Polygastiica. 



sessing internal partitions. In sea water, along witli tlie preceding. 

 Diameter l-240th. 



AcTiNOCYCLiJS senarius. — Discoid, cellular, with six rays and septa. 

 Diameter l-llSOth to l-720tli. Possil in the Schist of Oran in 

 Greek marl, and alive in the Baltic. 



(Group 132, Plate III., represents different views of this species.) 



A. hiternarius. — Like the preceding, hut without internal septa. 

 Found fossil in chalk, and alive at Hamburgh. 



A. octonarius. — Discoid, cellular, with eight rays and septa. 

 Diameter l-576th. Fossil in the chalk marl of Oran with A. senarius, 

 but less common. 



A. septenarius. — Eays seven, punctate ; no septa. Diameter 

 1-1 060th. to 1 -430th. Fossil in chalk marl, and alive in the Baltic. 



A. Sol. — Foimd by Ehrenberg at the mouth of the Elbe. Cha- 

 racters unknown. 



A. undulatus, (Kiitz.) — Eays six; disc flexnose; cells minute. 

 Fossil at Eichmond, Virginia. 



A. tredenarius. — I^o septa; thirteen rays. Diameter l-672nd. 

 Baltic. 



A. hiseptenarius. — No sejita ; fourteen rays. Diameter 1 -720th. 

 Fossil. 



A. quatuordena/rius, with fourteen rays, has also septa. 



A. bioctonarius, with sixteen rays, but differs from A. sedenarius, 

 by wanting septa. Size 1 -480th. Island Tjum, Gothland, and 

 Hamburg. 



A., septemdena/rius, with seventeen rays. 1- 468th. Bermuda. 



A. hinonarius, with eighteen rays. Chalk marl of -^gina and the 

 Greek Islands. 



A. vicenarius. — No septa; twenty rays. Diameter 1 -480th- 

 Island Tjorn. 



A. Lima. — No septa; twenty-one rays. Diameter 1 -480th. 

 Same locahty. 



A. Ceres. — No septa; twenty- two rays. Diameter 1 -336th. 



A. Juno, with twenty-three rays. 



A. Jwpiter. — Larger; no septa; twenty-four rays. Diameter 

 1 -432nd. Cuxliaven. 



