FOSSIL CORALS FROM WEST INDIES WELLS 95 



Family ASTROCOENIIDAE Koby 

 Genus ASTROCOENIA Milne Edwards and Haime, 1848 



ASTROCOENIA JAMAICAENSIS, new species 

 Plate 4, Figure 12 



Description. — Corallum more or less massive, upper surface irregu- 

 larly convex, sending up short protuberances. Corallites polygonal, 

 closely fused by their walls in the lower part of the corallum, but 

 often becoming slightly separated and cylindrical on the apices of 

 the protuberances. Calices shallow, polygonal or circular in shape, 

 separated by the fused corallite walls on which the upper ends of 

 the septa of adjoining calices meet, producing low granulations or 

 spines. Septa, 20 in number; 10 much larger than the rest and 

 extending to the columella, the others more or less rudimentary. 

 They are slightly granulate laterally, and the upper margins, which 

 slope at first gently, then abruptly, toward the columella, are very 

 lightly dentate. The columella is styliform, appearing in the bottom 

 of the calice as a round or slightly compressed tubercle. 

 Dissepmients sparsely developed. 



Measurements. — As follows : 



Specimen 1 represents a nearly complete corallum, whereas 2 and 

 3 are protuberances from a larger specimen. 



ry^e.— U.S.N.M. no. 44284. 



Occurrence. — Specimen 1 comes from the Velates schmiedeliana 

 bed of the Cambridge formation at Spring Mount; specimens 2 and 

 3 are from the Yellow limestone in the Cambridge district (Trech- 

 mann collection). 



Remarks. — This species is readily distinguished from the other 

 species of this genus of the West Indian Tertiary, except A. decatur- 

 ensis Vaughan (1919, p. 348) (lower and middle Oligocene), by 

 the constant decameral arrangement of the septa. In A. clecatur- 

 ensis the arrangement is usually octameral, as in the other species of 

 the West Indies, but it may be decameral occasionally. Comparison 

 with some other decameral species follows : 



