208 Vaughan Redes cription of a Coral. 



Not Platytrochus speciosus, C. W. Johnson, Geological 

 Survey, New Jersey, Ann. Rep. for 1897, p. 

 265, 1898; Platytrochus speciosus, C. W. John 

 son, Proc. Acad. Nat. Sci. Phila., 1898, p. 462, 

 = Trochocyathus woolmani, Vaughan, Proc, 

 Acad. Nat. Sci. Phila., 1900, pp. 436, 437, figs. 

 1,2,3. 



Corallum inversely conical, slightly curved, living attached by a rather 

 small base, transverse outline elliptical. 



DIMENSIONS: 



Greater transverse Lesser transverse Height of 

 diameter of calice diameter of calice corallum 



Specimen 1. 13.5mm. 11.5mm. 12.25mm. 



Specimen 2. 11 10 11 



The transverse measurements are made to the outer edge of the costae. 



Wall thin around upper edge, thicker below. 



Forty-eight costae, which are rather prominent, regularly alternately 

 larger and smaller, gradually decreasing in size and prominence as the 

 base is approached. Those corresponding to the fourth cycle of septa are 

 continued very near or actually to the base. Their edges are acute, 

 may be transversely undulated, serrately or crenately dentate, the serra 

 tions not very tall; small granulations on the sides. No vestige of 

 epitheca discernible. 



Septa rather thin, thicker at the wall, in four complete cycles, grouped 

 into six distinct systems. Members of the first and second cycles free; 

 those of the fourth joining by their inner margins to the sides of the 

 third. The upper margins of the larger septa may project as much as 

 1.25 mm. above the edge of the wall. Septal margins entire or very 

 faintly crenate. Lateral ornamentation, of granulations arranged along- 

 definite lines, with the line of divergence interior to the wall. 



Pali in two distinct crowns. Those before the septa of the first and 

 second cycles are situated far down in the otilice, but still distinctly above 

 the upper surface of the columella and are narrow. Those before the 

 third cycle extend high up into the calice, and are quite wide, usually 

 about twice as wide as those first described. All of the pali are thin and 

 transversely undulated. 



The calice is deep, I would say that its depth is about half the height 

 of the corallum. The upper surface of the columella is suddenly 

 sunken. 



Columella well developed, fascicular, composed of numerous twisted, 

 coalescing irregular laths. Its upper termination is not papillose, being 

 formed by the upper ends of the irregular laths. 



