﻿GEOLOGY AXD PALEONTOLOGY OF THE CANAL ZONE. 



371 



Gregory^ was mistaken in referring the specimens described by 

 him as EcMnoporafranTcsi (see pi. 84, fig. 4) to the genus Echinopora. 

 The following is the original description : 



Diagnosis. — ^The coral has a broad ba^e; from this pass outward short, thick, rapidly 

 tapering expansions. 



Corallites long, often an inch in length. Their distance one from the other varies 

 fi-om half then- diameter to the whole. 



Septa strongly dentate; inner teeth paliform, in three cycles. Those of the fii'st 

 cycle always unite to the columella; those of the second cycle often do so, but may 

 join the piimary septa; those of the third cycle are much smaller and independent, 

 but a few may unite with the septa of the other orders. 



Columella of very loose tissue; half the diameter of the corallite. Endotheca scanty. 

 Coenenchyma thinner than in other species of the genus. Echinulations of the siurface 

 coarse. Epitheca thick and well developed. 



Dimensions. — Diameter of an average corallite, 3 mm.; height of corallite varies 

 from 10 to to 25 mm.; thickness of wall varies from 1^ to 3 mm. 



Distribution. Recent: West Indies. Fossii: Barbados: Lowlevel Reefs, near 

 BridgetowTi. 



Cotypes. — ^British Museum (Natural History); a piece of one of 

 the cotypes in the United States National Museum, No. 156,455. 



A comparison of this description with the notes on the variation 

 of OrbiceUa annularis will show that it presents no important differ- 

 ence from variations of the species already recorded. Its growth 

 form is explanate, the exotheca is solid, and the secondary septa 

 often, but not always, reach the columella. 



B. Growth from columnar (pi. 84, figs. 3, 3a.) 



These are the specimens referred to in my paper "Some fossil 

 corals from the elevated reefs of Curasao, Arube, and Bonaire," ^ 

 obtained by Mr. v. Koolwijk at Westj^mit, Curasao. Three of the 

 specimens are in the United States National Museum, and they 

 form the basis of the following description : 



The corallum forms ascending, compressed, obtuse columns. 

 Dimensions in millimeters of variant of OrbiceUa annularis from Curacao. 



Calices 2.5 to 3.5 mm. in diameter; from less than 1 mm, to 2 mm. 

 apart. The upper margin is usually not elevated, while the lower 

 one is, thus tilting the calicular orifices. The maximum length of 

 the lower limb of the calice is about 3 mm. Subequal, relatively 

 thick, dentate costae correspond to all septa. 



1 Geol. Soc. London Quart. Jour., vol. 51, p. 274, pi. 11, figs. 2a, 26, 1895. 



2 Geolog. Keichs. Mus. Leiden Samml., ser. 2, vol. 2, Heft I, p. 26. 



