GEOLOGY AND PALEONTOLOGY OE THE CANAL ZONE. 475 



on plate 135, figure 5. The lesser diameter of the three larger coral- 

 lites is 19 mm. ; the greater diameter ranges from 21 to about 23 mm. 

 The calices of this specimen are shallow. In the calice represented 

 by plate 135, figure 5b, it will be seen that the primary and secondary 

 septa are subequal and are thicker than the members of the higher 

 cycles. There are about 86 septa in this calice — that is, there are 4 

 complete cycles and 38 quinaries. The primaries and secondaries 

 are solid for the most part; the tertiaries are somewhat thinner and 

 near the columella they are represented by only partially fused 

 septal tabeculae. The quaternaries are thinner and more perforate 

 than the tertiaries, to which they fuse by their inner ends rather 

 near the columella. The quinary septa are still thinner and very 

 perforate; they tend to fuse to the sides of the included quaternary. 

 On the inner part of the largest septa are indefinite lobes or teeth, 

 some of which simulate partially developed paliform lobes. Synap- 

 ticulae are greatly developed, between both the costae and the septa; 

 and there are endothecal dissepiments. 



Specimen No. 4- — This specimen is composed of seven corrallites, 

 plate 137, figure 1. It differs from specimen No. 3 principally by 

 having deeper calices and on some of the large septa there are fairly 

 well-developed paliform lobes. 



Specimen No. 5. — Plate 136, figures 1, 15, are two views, natural 

 size, of a specimen that is essentially typical variety nobilis of Duncan. 

 It differs from the typical form of the species by having somewhat 

 smaller corrallites and consequently less numerous septa. Specimens 

 bridging the slight gap between specimens Nos. 4 and 5 might be 

 described, but to do so seems unnecessary. 



The foregoing descriptions apply to the typical form of the species; 

 some variants will now be considered. 



Specimen No. 6. — Plate 137, figure 3, represents a calice and inter 

 calicular areas in a specimen that differs from specimen No. 3 chiefly 

 by the nonexsert calicular margins. 



Specimen No. 7. — The calices represented by plate 137, figures 4, 4a, 

 are of a specimen that practically intergrades with specimen No. 6. 

 The calices illustrated are smaller and the septo-costae coarser than 

 in specimen No. 6. Plate 137, figure 5, illustrates a closely similar 

 specimen from the base of the Chattahoochee formation, on Flint 

 River, about 4 miles below Bainbridge, Georgia. The calices of the 

 Bainbridge specimens are excavated, thereby differing from specimen 

 No. 7. 



Specimen No. 8.— This specimen, plate 137, figure 2, has corallites 

 that are more prominent and more isolated than in the other 

 specimens described, and the costae on the free corallite limbs are 

 mostly subequal. 



