GEOLOGY AND PALEONTOLOGY OF THE CANAL ZONE. 445 



cate around the edge. Transverse diameters, 36 by 38 mm.: height 

 26 mm. 



Calices irregularly polygonal, excavated on top of the corallum, but 

 shallow near its edges. Length of largest calices, 5.5 mm. ; width 

 of largest calices, 3.5 to 4 mm.: 4 to 4.5 mm. about the usual diame- 

 ter; depth between 2 and 2.25 mm. The area between adjacent 

 calicular depressions is relatively acute, the wall usually traceable 

 xilong the summit as a slightly raised zigzag or straight line. 



Septa thicker than the width of the interseptal loculi; four com- 

 plete cycles and in the larger calices some quinaries; primaries and 

 secondaries extend to the columella, subequal, or the primaries 

 slightly larger; tertiaries fuse to the included secondary about two- 

 thirds the distance from the wall to the center of the calice or very 

 near the columella; quaternaries fuse to the included tertiary about 

 one-third or one-half the distance from the wall to the calicular 

 center; quinaries where present fuse to the included quaternary. 



Septal margins slope gently from the wall to about half the distance 

 toward the calicular center and then incline steeply to the outer edge 

 of the columella. The dentations are small, crowded, and bluntish 

 or rather acute, more pointed near the columella, compressed in 

 planes transverse to the septal planes; 15 were counted on a septum 

 2.5 mm. long; in other words, 6 within 1 mm. 



Synapticulae crowded near the wall, 3 within 1 mm. measured 

 down the septal slope from the wall edge. 



Columella small, false, papillary; a central, styliform papilla notice- 

 able in many calices. 



Description of a specimen, collected by Miss C. J. Maury in Santo 

 Domingo, Rio Cana, zone H (pi. 122, figs. 2, 2a, 2b). — Corallum a small 

 mass, with a flattish base and a rounded upper surface. Diameter, 

 26 by 28 mm.; height, 15 mm. 



Calices shallow, polygonal, usually one diameter longer than the 

 other, separated by narrow, straight, or zigzag walls. Diameter of 

 largest calice, 6 mm. ; about 4 mm. a usual measure of the diameter. 



In the largest calice (6 mm. in diameter) there are 52 septa, which, 

 according to the usual practice of assigning septa to cycles, would 

 represent 4 complete cycles and 4 quinary septa. Fifteen septa, 

 6 primaries, 6 secondaries, and 3 tertiaries, extend to the columella, 

 and 2 other tertiaries fuse to the included secondary almost at the 

 periphery of the columella. Where quinary septa are present it is 

 difficult to distinguish between primaries and secondaries, and 

 between the elongate tertiaries and the secondaries. In a calice 4 

 mm. in diameter the septal arrangement is more definite; there are 

 46 septa, the quaternaries not being developed in one quarter 

 system. The tertiaries fuse to the secondaries either rather near 



