GEOLOGY AND PALEONTOLOGY OF THE CANAL ZONE. 335 



The branch terminals are compressed and often form sinuous 

 plates. Thickness just below the summits about 3 mm.; width very 

 variable, ranges from 6 or 7 up to 25 mm. Nodule-like growths are 

 frequent on the sides of older branches. 



Calices on older parts of the corallum from 1 to 1.3 mm, in diameter, 

 therefore rather large and conspicuous; intervening walls from 0.75 

 to 2 mm. across, usually about 1.25 mm. Near and on the branch 

 summits the calices are usually crowded and slightly less than 1 mm. 

 in diameter. Upper margin of the calices usually more prominent 

 than the lower, sloping slightly downward, externally finely costulate. 



Septa, 6 primaries distinct, well developed, extending to the col- 

 umella, the directives more prominent than the other primaries; 

 secondaries are small or obsolete, if they were present they usually 

 have been destroyed in the type and paratypes of the species. 



Columella, a small, only slightly prominent style. 



Coenenchyma dense; its surface beset with pointed granulations. 



Localities and geologic occurrence. — Canal Zone stations 6016, in the 

 Emperador limestone, quarry. Empire, where some hundreds of 

 specimens were obtained; 6024&, lower end of culvert, Panama 

 Railroad (relocated line), on Rio Agua Salud, in the upper bed, col- 

 lected by T. W. Vaughan and D. F. MacDonald. Station 6026, in the 

 Culebra formation, 2| miles south of Monte Lirio, Panama Railroad 

 (relocated line), collected by T. W. Vaughan and D. F. MacDonald. 



Anguilla, station 6894, bluff, south side of Crocus Bay, in the lower 

 50 feet of the exposure, collected by T. W. Vaughan. (See pi. 

 74, figs. 4, 4a.) 



Doctor MacDonald obtained the specimen represented by plate 

 74, figure 5, at station 1863 of the canal commission, on the west 

 side of Gaillard Cut, between points opposite Cucaracha and Paraiso, 

 station 5853 of the United States National Museum locality register. 

 The specimen came from a layer, about 2^ feet thick, consisting of 

 pebbles, gravel, and tuffs cemented with calcareous material; below 

 the layer is gray, flaggy sandstone and tuff beds; above it is gray, 

 flaggy sandstone, in thin layers separated by partings of carbonaceous 

 black shale. The geologic horizon therefore seems to be in the Culebra 

 formation, probably near its top. The specimen appears to be a form 

 of StylopJiora imperatoris in which the calices are more crowded than 

 usual, as it agrees with that species in all other characters. 



Type.~No. 324752, U.S.N.M. 



Paratypes.— 'No^. 324753, 324754, U.S.N.M. 



STYLOPHORA PANAMENSIS. new species. 



Plate 75, figs. 1, la. 



Corallum, branches more or less contorted plates (see pi. 75, fig. 1). 

 The thickness of the lower end of the type is 12.5 mm.; width, 

 exceeds 28 mm.; length from base to summit, 38 mm. 



