442 SYSTEMATIC PALEONTOLOGY 



pansion. Individual corallites divergent, but usually touching at their 

 bases. Walls very thin at their calicular edge, thicker below. Epitheca 

 extremely thin, finely granulated and in some forms showing parallel, 

 somewhat sinuous, flat, broad strine, corresponding to the costse and ex- 

 tending to the base. Costse distinct just below the calicular edge, not 

 very prominent, alternately larger and smaller, sometimes slightly 

 crested. Calices deep, as a rule circular, at times considerably com- 

 pressed, 5 to 8 mm. in diameter. Septa thin, inucli narrowed at tlu' lop. 

 in mature corallites in four complete cycles ; septa of the last cycle much 

 thinner and narrower than those of the preceding, often merely rudi- 

 mentary; in the younger individuals septa but thirty-six; there is a ten- 

 dency for the younger septa to turn toward and unite with the next 

 older; inner edges strongly dentate, teeth frequently truncated or 

 rounded, slightly coarser near the columella; sides granulated, though 

 not stoutly so.. Columella small, false, composed of more or less inter- 

 locking or twisted processes from the inner ends of the septa. Multipli- 

 cation by budding chiefly from basal expansions, although it may take 

 place well up on the side of the parent corallite. 



Occurrence. — Chesapeake Group. Bellefield, Yorktown, Carter's 

 Landing, and City Point, Virginia. 



Collections.— J o\\ns Hopkins University, U. S. National Museum, 

 Philadelphia Academy of Sciences, Wagner Free Institute of Science. 



Subgenus CCENANGIA Venill. 



AsTRANGiA (Cgenangia) conradi n. sp. 

 Plate CXXV, Figs. 1, 2. 



Astrmi hella Tuomey and Holmes, 1857, Pleit)ceue Fossils of South Carolina, \\ 1, 



pi. i, ligs. 1, la. 

 Cmnangia bella Gane, 189.5, Johns Hopkins Univ. Circ, vol. xv, No. 131, p. 9. 

 Ccenangia helhi Gane, 1900, Proc. U. S. Nat. Museum, vol. xxii, p. 189. 

 Astrangia (Cminngia) helhi Vaughan, 1901, Bull. U. S. Fish Com. for 1900, vol. ii, 



p. 299. 

 Astrea hdla Conrad, 1841, Proc. Acad. Nat. Sci. Phila., vol. i, p. 33. 



Description. — The following description is the one published by Gane 

 for Ccsnangia hella, somewhat modified : 



Colony encrusting. Corallites thin walled, closely united. Calices 

 irregularly prismatic, quite deep, with their fossae narrow at the bottom ; 



