GEOLOGY AND PALEONTOLOGY OF THE CANAL ZONE. 



371 



Gregory 1 was mistaken in referring the specimens described by 

 him as EcMnopora franksi (see pi. 84, fig. 4) to the genus EcMnopora. 

 The following is the original description : 



• Diagnosis .—The coral has a broad base; from this pass outwai'd short, thick, rapidly 

 tapering expansions. 



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

 from half their diameter to the whole. 



Septa strongly dentate; inner teeth paliform, in three cycles. Those of the first 

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

 join the primary 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. 

 Ooenenchyma thinner than in other species of the genus. Echinulations of the surface 

 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. Fossil: Barbados: Lowlevel Reefs, near 

 Bridgetown. 



Ooiypes. — 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 Orhicella 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 Curacao, Arube, and Bonaire," 2 

 obtained by Mr. v. Koolwijk at Westpunt, Curacao. 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 Orhicella annularis from Curasao. 



Specimen No. 



Greater 

 diameter 

 of base. 



Lesser 

 diameter 

 of base. 



Height. 



Remarks. 



1 



mm. 

 37.5 

 30+ 



27.5 



mm. 

 25 

 23- 



21 



mm. 

 60 

 71 



91 





2 



Constricted above base; gradually enlarging 



above the constriction. 

 Figured, pi. 84, figs. 3, 3a. 







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 



maximum length of 



one is, thus tilting the calicular orifices. Th 



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



thick, dentate costae correspond to all septa. 



1 Geol. Soe. London Quart. Jour., vol. 51, p. 274, pi. 11, figs. 2a, 25, 1895. 



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



