Isastraea turbinata 
regularly pentagonal, not deep, and not packed geometrically. 
Margins existing as sharp ridges, not marked by the septa, but 
faintly ragged; united, crowded, not deep* Septa small, not 
exsert, not arched, but slanting irregularly downwards and in- 
wards, except the primary, which stand up in the fossa, and are 
easily seen; they are laminar, delicate, and crowded, slightly 
toothed near the internal end, ragged above, and granular on the 
sides. The primary septa sometimes meet by their inner ends; 
the secondary and tertiary are subequal when there are others. 
They are disposed in six systems. In fully developed calices 
there are four cycles in four systems, and three in the rest; in 
other calices three cycles with an occasional fourth order; the 
fourth cycle is very small. Septa straight, not crenulate, but 
slightly ragged; no|fext9rnal spines. Endotheca tolerably developed. 
From the condition of the base, which has been rolled, no epitheoa 
can be seen. Reproduction by submarginal (close to the wall) gem- 
mation. Diameter of the calices from 2 lines to 3 l/2 lines. 
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