GEOLOGY AND PALEONTOLOGY OF THE CANAL ZONE. 375 



Gregory refers Heliastraea altissima Duncan to the s3monymy of 

 this species, but I doubt the correctness of his conclusion and am 

 treating it as vahd. 



Geologic distribution. — Pleistocene and Recent, throughout the 

 olovatod reef areas of the West Indies, eastern Central America, and 

 Florida. 



Duncan ^ has listed Astraea harhadensis, one of the synonyms of 

 0. annularis, from the "marl formation" of Antigua, remarking that it 

 is "greatly altered by f ossilization ; the calicular surface is subplane, 

 and the calices are seen as prominent columnar casts." Should 

 Dmican's identification bo correct, the geologic range of 0. annularis 

 extends from Oligocene time to the present. Mr. R. T. Hill obtained 

 in Antigua a silicified specimen that looks like 0. annularis, but I am 

 not sure that it is that species. 



Costa Rica, station 4269, Port Limon, collected by Doctor Wailes 

 in beds referred to the Pliocene. There are three dissociated coral- 

 lites which have the general characters of Oriicella annularis, but are 

 not absolutely typical, for the primary septa are appreciably but not 

 strikingly thicker than the secondaries. They are, therefore, somewhat 

 intermediate between typical examples of the species and Orhicella 

 limhata (Dmican). 



2, ORBICELLA LIMBATA (Duncan). 



Plate 85, figs. 1, la, 2, 2a, 2b, 3, 4, 4a. 



1863. Phyllocoenia scul-pta var. tegula Duncan, Geol. Soc. London Quart. Journ., 

 vol. 19, p. 432. 



1863. Phyllocoenia limbata Duncan, Geol. Soc. London Quart. Journ., vol. 19, 



p. 433. 



1864. Plesiastraea ramea Duncan, Geol. Soc. London Quart. Joui'n., vol. 20, p. 



39, pi. 5, figs, la, lb. 

 1866. Phyllocoenia limbata Duchassaing and Michelotti, Sup. M4m. Corall. 



Antilles, p. 76 (of reprint). 

 1866. Plesiastraea ramea Duchassaing and Michelotti, Sup. M6m. Corall. 



Antilles, p. 87 (of reprint). 

 1868. Phyllocoenia limbata Duncan, Geol. Soc. London Quart. Journ., vol. 24, 



p. 23. 

 1868. Plesiastraea ramea Duncan, Geol. Soc. London Quart. Journ., vol. 24, p. 25. 

 1870. Phyllocoenia limbata Duchassaing, Rev. Zooph. et Spong. Antilles, p. 28. 

 1870. Plesiastraea ramea Duchassaing, Rev. Zooph. et. Spong. Antilles, p. 30. 



Original description of PJiyllocoenia limhata: ^ 



Corallum in the shape of Stylina limbata Edwards and Haime. Stem large 

 and cylindrical. (?orallites numerous, irregularly placed. Calices separated by 

 much coenenchyma, circular and but slightly elevated. Costae covering much 

 surface. Slightly dentate where they approach, and turning aside from those of other 

 calices; they are not continuous, not very prominent, and slightly granular. Septa 

 not projecting far inwards, laminae granular; their upper margin is neither incised nor 

 dentate; in six systems of generally three cycles, though occasionally of four. Pri- 



1 Geol. Soc. London Quart. Joum., vol. 19, 1863, p. 433. 

 37149— 19— Bull. 103 13 



