Descriptions of Devoxiax Fossils. 233 



the edge; transverse diaplirag-nis broad, siuootli, slightly convex, and 

 closely arranged ; outer portion of the body closely and minutely 

 vesiculose. 



Formation and locality. In the marly beds at Eockford, Iowa. 



Genus — CHONOPHYLLUM^'^ Ed. & Haime. 

 Chonophtllum (Pttchophyllum) ellipticitm n. 8p. 



Plate 9, fl«. 13. 



Coral small, subturbinate, laterally compressed, and much distorted 

 in growth ; rays somewhat sti'ongly developed and numerous, very 

 slightly twisted as they approach the center of the cup. Calyx shallow, 

 with rapidly ascending sides in young specimens, and spreading nearly 

 horizontally toward the margin in older forms. Exterior of the body 

 covered by a continuous epithecal coating, increasing in strength from 

 below upward. In a vertical section the infundibuliform cups are 

 somewhat distant, broad at the base, with rapidly ascending sides ; the 

 spaces between them, and also between the rays, are tilled with numer 

 ous, irregular, cystose partitions. 



The distinctive features of this species consist in its elliptical outline 

 and distinctly marked rays. There may be some doubt as to its ge- 

 neric relations. The rays are very sliglitly twisted as they approach tlie 

 center of the cup, but there is no appearance of a columella. The 

 great development of the rays, and the continuous epithecal coating, 

 are features which pertain more particularly to Ptyciiophyllum than 

 to Chonophtllum. 



Format/ion and looality. In the marly beds at Eockford, Iowa. 



Genus — ACERVULARIA Schweig. 



ACEEVULARIA INEQUALIS n. Sp. 

 Plate 9, flgs. 11, 12. 



Coral forming convex masses several inches in diameter. Cells very 

 irregular, seldom exceeding a fourth of an inch in diameter, while fully 

 one-fourth of those constituting the mass do not exceed an eighth of 

 an inch ; the central depression of the cell forms about one-half of its 

 diameter, and is usually about half as deep as wide, with a very slightly 

 elevated center. Rays well developed, corrugated on their sides and 

 edges, numbering about twenty-eight in the larger cells, of Avhich 

 one-half extend into the central depression, while the remainder reach 

 only to its margin or but slightly down beyond ; in the smaller cells 

 the rays are less fully developed, and number from twenty-live to 



*Tliis genua is apparently identical with Choxophyllum Hall, Palceontolorjij of Xew 

 York, vol. 3, piiblislied in 1853, though actually in print more than two years earlier 



[Assem. No. 133.] 30 



