﻿GEOLOGY AND PALEONTOLOGY OF THE CANAL ZONE. 401 



secondaries; paliform lobes insignificant or absent. Columella with 

 papillate upper surface. 



Duncan's Plesiastraea distant; and P. globosa, from the silt of the 

 sandstone plain of Santo Domingo, belong in the same synonymy. 

 The types of both species are preserved in the collection of the 

 Geological Society of London, where I have studied them. A dupli- 

 cate ol the latter is in the United States National Museum. The 

 difference between P. distans and P. globosa consists in the calices 

 of the former being one-half or more than one-half their diameter 

 apart, while in the latter the distance between them is usually less 

 than one-half this diameter. 



Cyphastrea, hyades and C. hournoni are closely related species. The 

 caJices of (J. hyades, however, are constantly larger than those of 

 C. hournoni, and the tertiary septa, except in young coralla, con- 

 stantly fuse to the sides of the secondaries. C. houmoni has smaller 

 calices, and except when the pali are decidedly thickened, has the 

 inner ends of the tertiary septa free. These dift'erences are constant 

 in tlic considerable suites of specimens that I have been able to study. 



Localitif.s arul geologic occurrence. — Living at St. Thomas, Virgin 

 Islands, whence Duchassaing had a number of specimens. Tortugas, 

 Florida, in water between 8 and 9 fathoms deep. 



Pliocene, in the Caloosahatchee marl of Florida, on Caloosahatchee 

 liiver, collected by Frank Burns and others; and Shell Creek, 

 Florida, collected by Frank Burns and by Doctor Griffith. 



Miocene, Rio Cana, Zone H, Santo Domingo, collected by Miss 

 C. J. Maury in association with an in^'ertebrate fauna of the age of 

 the Bowden marl of Jamaica. 



Miocene, in the La Cruz marl, Santiago, Cuba, at stations 8436, 

 3437, 3446, collected by T. W. Vaughan, in association with an 

 invertebrate fauna closely related to, but probably a little younger 

 than that of the Bowden horizon. 



ANTIGUASTREA, new genus. 



Growth form massive; asexual reproduction by intercorallite 

 i)udding; septal margins very obscurely dentate, subentire; coral, 

 lites usually joined by thin costae; columella lamellar, usually well 

 developed and prominent; exothecal and endothecal dissepiments 

 highly developed. 



Type-species. — Astraea cellulosa Duncan. 



This genus is near Orhicella, from which it differs by its more 

 obscurely dentate septa and its lamellar columella. The costae 

 between corallites are thin and in some instances disappear on the 

 surface of the exothecal vesicles. 



