GEOLOGY AND PALEONTOLOGY OF THE CANAL ZONE. 485 



Locality and geologic occurrence. — Antigua, Morris Looby's Hill, in 

 the Antigua formation, collected by R. T. Hill. 



Georgia, station No. 3381, Russell Spring, Flint River, Decatur 

 County, Georgia, collected by T. W. Vaughan, in the base of the 

 Chattahoochee formation. 



Canal Zone, station No. 6026, 2 miles south of Monte Lirio, col- 

 lected by T. W. Vaughan and D. F. MacDonald in the Culebra 

 formation. 



Type. — Museum of Comparative Zoology. 



Paratype. — Ho. 325609, U.S.N.M.; also other specimens. 



Comparison of the specimens from near Bainbridge, Georgia, with 

 the smaller specimens from Antigua, fails to reveal any difference 

 whatever between the specimens; and no noteworthy difference is 

 seen between the other specimens and -the best one from near Monte 

 Lirio. 



ASTREOPORA PORTORICENSIS, new species. 



Plate 140, figs. 2, 2a. 



Corallum ramose, branches subcircular or elliptical in cross- 

 section. Length of type, 56 mm.; greater diameter of lower end, 

 16 mm., lesser, 13 mm.; width of upper end (which is bifurcating) 

 about 30 mm. 



Calices moderately deep, usually deformed, one diameter longer 

 than the other. A small calice has a greater diameter of 1.7 mm., 

 lesser, 1.3 mm.; a rather large calice has diameters measuring 2.3 

 and 1.6 mm., respectively. The distance apart of the calices varies 

 from 1.3 to slightly more than 2 mm. Calicular margins scarcely 

 elevated; there is really no distinctly elevated rim. 



Septa, in the larger calices, in three cycles, the last very small; 

 their outer ends thick, the inner portions thin. Upper margins very 

 slightly exsert. 



Columella, poorly developed. 



Coenenchymal surface usually coated by basal deposit, but in 

 places costae with intervening perforations are obvious. 



Locality and geologic occurrence. — Porto Rico, station 3191, 4 miles 

 west of Lares, Pepino formation, collected by R. T. Hill. 



Type.— No. 325306, U.S.N.M. 



This species is very near Astreopora antiguensis; in fact, I am by no 

 means sure that they are really distinct. The type of A. portoricensis 

 has smaller and less prominent calices; but some of the specimens of 

 A. antiguensis from Bainbridge, Georgia, have small calices. The 

 critical difference, therefore, consists in the low, nonprotuberant 

 calices of A. portoricensis, a difference which, according to the 

 available material, is valid. 



