GEOLOGY AND PALEONTOLOGY OP THE CANAL ZONE. 45 T 



CYATHOMORPHA HILLI, new species. 



Plate 124, figs. 1, la; plate 125, figs. 1, la, lb, 3c, Id, 2, 2a. 



Corallum with a small base, above which it increased in diameter; 

 upper surface rounded; calices confined to the upper curvature; 

 base and sides below the level of the calices naked, not even shreds 

 of epitheca were observed. Below the caUces, the sides of the cora 1 - 

 lum grow outward by the superposition of costate layers, each outer 

 layer resting on the costae oi the next inner layer, except at the 

 lower edge where it may flare outward. The layers range in thick- 

 ness from 0.5 and 1.5 mm.; usually they are imperforate, but in 

 places perforations and synapticulae can be clearly recognized. 

 The costae are narrow, steep-sided, fairly prominent, acute or 

 rounded on the edges; distance between costal summits from 0.75 to 

 1.5 mm. The type is 112 mm. in horizontal diameter and 80 mm. tall. 



Corallites protuberant from 1.5 up to more than 10 mm., average 

 5 or 6 mm. ; distance between thecal summits of neighboring coral- 

 lites from 3 to 10 mm., or even more. Corallite walls with a rather 

 sharp upper edge; mostly imperforate. Some perforations and 

 synapticulae, especially near the upper edges. Septo-costae low, 

 subequal, wide, flatfish or rounded in profile. 



Calices subcircular, broadly elliptical, or compressed elliptical in 

 outline. A large subcircular calice on the type is 18 mm. in diam- 

 eter; a small, but apparently fully developed calice, on the same 

 specimen, is 10 by 13 mm. in diameter; the shorter diameter of 

 young calices is only 8 mm. The calices of the type are larger than 

 those of the other specimens of the species. In paratype No. 1 

 (pi. 125, fig. 1), the largest calice is 11.5 by 13.5 mm. in diameter; 

 the smallest is 8 by 13 mm. in diameter. In paratype No. 2 (pi. 125, 

 fig. 2), the largest calice is 13.5 by 16.5 mm.; the smallest, 10 mm. 

 in diameter. Unless the calices are young or stunted the average 

 of the two diameters is rarely below 10 mm. Depth of calices slight, 

 about 4 mm. a maximum; columellar fossa not deep. 



The number of septa in the calice represented by plate 125, fig. lc, 

 paratype No. 1, is 70. This calice is 11.5 by 13.5 mm. in diameter, 

 and is of the size about normal for the species. It has four com- 

 plete cycles of septa and 22 quinaries. About 8 of the septa are 

 thicker than the others, and bear thick paliform lobes which are 

 fully half the width of the septa. These 8 septa and about 15 

 thinner septa extend to the columella; the thinner septa also bear 

 wide paliform lobes. In general in a half or quarter system the 

 septa of the penultimate cycle fuse to the sides of the included mem- 

 ber of the next lower cycle, while the members of the last cycle are 

 small. All except the smallest septa bear paliform lobes. Septal 

 margins low over the wall, subentire; within the calice the thicker 



