FOSSIL CORALS FROM WEST INDIES WELLS 



87 



of the fifth ; the inner ends of the fifth cycle — that is, those nearest 

 the primaries and secondaries — are fused to the third cycle near the 

 columella; the sixth cycle fuses to the fifth, and those of the sev- 

 enth, which are developed near the primaries, fuse to the sixth. The 

 structure of the septa is trabeculate-fenestrate, the pores being filled 

 up below, and perforations, except of the upper parts of the septa 

 of the higher cycles, are rare. The columella is well developed, essen- 

 tial, elongate, completely filling the fossette, with a papillose upper 

 surface. Synapticulae are present mainly in the peripheral region. 

 The wall is indistinct. There are no dissepiments. 

 Measurements. — As follows : 



Type.—V.S.^M. no. 74489. 



Occurrence. — From a locality near Catadupa, Jamaica (Trech- 

 mann collection). 



Remarks. — Specimen 2 is an immature one, in which the corallum 

 is discoid or plano-convex (pi. 3, figs. 8, 9) ; the septa are much 

 thinner and more finely denticulate than in specimen 1, upon which 

 the foregoing description was mainly based. 



Genus SYNASTREA Milne Edwards and Haime, 1848 



SYNASTREA (7) ADKINSI. new gpecies 



Platb 3, Figures 14, 15 



Description. — Corallum massive, tuberous, increasing in size by 

 superposition of concentric layers about 5 mm thick, the exposed 

 margins of these layers being covered by a thin epitheca. The cal- 

 ices are distinct, close-set, nearly always separated by an intercoral- 

 lite groove. Where they are separated to any extent they are cir- 

 cular in outline, where close-set they are polygonal. The average 

 diameter within the margins is 2.75 mm; the distance between cen- 

 ters varies from 5 to 6.5 mm; the maximum height of the margins 

 above the intercorallite grooves is about 0.3 mm ; the average calicu- 

 lar depth is 0.75 mm, but is often increased by weathering. There 

 is no corallite wall, and the septocostae are confluent. The septa, 

 40 to 60 in number, comprise four complete cycles and parts of the 

 fifth. In structure they are trabeculate-fenestrate near the surface, 



73594—34 3 .._ 



