GEOLOGY AND PALEONTOLOGY OP THE CANAL ZONE. 347 



Astrocoenia d'achiardii was described from the upper Eocene of St. 

 Bartholomew. Finding it on the Pacific coast of Nicaragua is addi- 

 tional evidence in favor of connection between the Atlantic and Pacific 

 oceans across Central America during upper Eocene time. 



ASTROCOENIA GUANTANAMENSIS, new species. 



Plate 79, figs. 1, la, 2. 



Corallum massive, with a rather uniformly romided or more or less 

 tuberose surface. Type 55 mm. long, maximum width about 31 mm., 

 height 38 mm. The corallum may be much larger. 



Calices polygonal, shallow, almost superficial, small; maximum 

 size about 1.75 mm. in diameter, 1.5 mm. usual, smallest calices 

 about 1 mm. in diameter, measured between thecal summits. Inter- 

 corallite walls acute or flattish, usually less than 0.25 mm. wide, 

 maximum width 0.5 mm.; crossed by subequal costae corresponding 

 to all septa unless very narrow, when the edge of the wall is dentate 

 instead of costate. 



Septa 16 in number, 8 reach the columella; 8 small, about half 

 the length of the principals; in most instances they are thicker in 

 the wall than at their inner ends. Margins of the longer with about 

 three dentations on each. Septal faces with sharp granulations. 



Columella, a small, erect, central style. 



Localities and geologic occurrence. — Cuba, station 7522, Mogote 

 Peak, 0.5 mile east of east boundary of United States Naval Reser- 

 vation, Guantanamo, south side of peak, altitude about 375 feet a. t., 

 collected by O. E. Meinzer (type) . 



Antigua, station 6865, Jackass Point, St. John, collected by T. W. 

 Vaughan. 



Panama, station 6587, Tonosi, collected by D. F. MacDonald. 



Type— No. 324794, U.S.N.M. • 



Astrocoenia guantanamensis is most nearly related to Astrocoenia 

 incrustans (Duncan) which is from the upper Eocene St. Bartholo- 

 mew limestone, and is the next species here described. The calices 

 of A. incrustans, a description of which follows, are rather deep and 

 the intercorallite areas are flattish and costate. 



ASTROCOENIA INCRUSTANS (Duncan). 



1873. Stephanocoenia incrustans Duncan, Geol. Soc. London Quart. Journ., 



vol. 29, p. 553, pi. 20, fig. 6. 

 1899. Stephanocoenia incrustans Vaughan, Mus. Comp. Zool. Bull., vol. 34, 



p. 229. 



Original description. — "The corallum is low in height, and in crusts 

 rocky surfaces. The corallites are united by their rather thick walls, 

 and are parallel. The calices are quadrangular or pentangular, and 

 their margins are marked by the septa of the adjacent corallites. 



