GEOLOGY AND PALEONTOLOGY OF THE CANAL ZONE. 449 



just described, but in other calices the septa arid columella are thick- 

 ened, the columella in some calices being a more or less papillate 

 compressed axial plug. The variation from the normal is similar to 

 the variation exhibited by the specimens of 8. siderea from a depth 

 of about 9 fathoms south of Tortugas, described on page 444. 



Another specimen from Ballast Point has calices up to as large as 

 5 by 6.5 mm. in diameter. A large calice has 64 speta. Except in 

 having rather large calices and correspondingly more septa, this 

 specimen does not seem to differ in any important particular from 

 the type of the species. 



Plate 117, figures 1, la, lb, illustrates a variant from Coronet 

 Phosphate Mine, station No. 6043, G. C. Matson collector. The 

 calices in it are from 7 to a little more than 8 mm. in diameter. A 

 calice, 6.5 by 8 mm. in diameter, of this specimen has 66 septa. 



A specimen from station 6084, Withlacoochee River, 3 miles below 

 Valdosta, Lowndes County, Georgia, has in a calice 6 by 7 mm. in 

 diameter 64 septa and in a calice 5.5 by 7 mm. in diameter 72 septa. 

 This specimen very closely approaches S. conferta (Duncan), but 

 appears to have on the average fewer septa than S. conferta. Perhaps 

 these specimens that have over 60 septa should be separated from 

 S. silecensis and either referred to a new species or to 8. conferta. 

 At one time I referred them to S. conferta, but their average fewer 

 septa according to the size of calices as compared with S. conferta, 

 led me to consider them and the specimen next to be described as 

 belonging to a different species. 



Description of a specimen from station 3381 , Flint River, 4 Wiles 

 below Bainbridge, Georgia (pi. 118, figs. 1, la). — Corallum subdiscoid 

 in form. Its greater transverse, diameter 45 mm.; lesser transverse 

 diameter, about 38 mm.; thickness, 14 mm. Upper and lower sur- 

 face, subplane, somewhat undulated. 



Calices irregularly hexagonal or pentagonal in shape, fairly large, 

 range in diameter from 4 to 6.5 mm.; rather shallow or superficial. 



Septa numerous, in one calice 6.5 mm. long by 4.5 mm. wide 58 

 were counted. There are, applying the ordinary method of distri- 

 buting septa into cycles according to the number, four complete 

 cycles and a fair number of members of a fifth. The various cycles 

 are not distinctly marked. The septal margins in places slope from 

 an acute ridge to the bottom of a moderately deep calice; in other 

 places the calices are shallow, superficial, the septal margins flat- 

 tened from above, no ridge being present. The dentations on the 

 septal margins are rounded; there are about 10 within 2 mm. Some 

 septa are perforated between the trabeculae, but it seems probable 

 that these perforations are of secondary origin, resulting from the 

 solution of the septa in the thinnest places during fossilization. 



Synapticulae are very abundant, especially well developed in 

 several, at least "two or three, vertical series near the outer boundary 



