I02 



Localities. — L, 22 specimens, Vasco da Gama, N., 71° E., 

 i8i miles, stones. II., 6, Vasco da Gama, S., 75° E., 13! miles, 

 black specks. III., i, Cape Point Lighthouse, E., 26|- miles, 

 sand, black specks, and coral. IV., i, Buffalo River, N., 15 

 miles, coral and mud. V., 2, lat. 30° 3' S., long 27° 57' E., 

 sand, shell, and rock. VI., 2, Cape St. Blaize, N.W. \ N., 30 

 miles, rock. VII., 4, Cape Vidal, N.N.E. \ N., (^\ miles, rock. 



The nature of the adult pali and columella cannot be clearly 

 understood without a knowledge of their gradual development 

 (PI. II., figs. A-E). The earliest stage could be seen only in 

 sections, where there were 12 septa, 6 pali, and one rod in the 

 columella. The smallest corallum. No. 38, is in a slightly later 

 stage ; the pali are somewhat indefinite, and there are several 

 rods in the columella. The other coralla of VII. and Nos. i, 2, 

 and 3 have 12 rather oval-shaped pali, situated before the septa 

 of cycles I .and II. Those before cycle I. are nearer to the 

 centre of the axial fossa, and in the largest specimens merge 

 into the rods which form the columella, not being clearly dis- 

 tinguishable from them, though their separate origin is clearly 

 shown in sections. 



In the specimens from station I. every stage between the 

 last could be followed to the fully adult, with well-formed, more- 

 flattened tertiary pali. Although scarcely typical, in the largest 

 specimens there seemed to be a tendency for the tertiary pali to 

 push the secondary pali into the centre of the fossa, where they 

 simply appeared as rather more flattened rods at the sides of 

 the columella, opposite the pomts of the chevron then formed 

 by the tertiary paii alone. Occasionally the secondary pali be- 

 come fused with the tertiary. 



The variation in the septa may best be seen by reference to 

 the table. It appears to be mainly due to growth, only two 

 specimens showing radial, i.e., meristic variation, one having 5 

 and the other 7 systems.. The specimens, in addition, differed 

 materially from one another in the number of the rods of the 

 columella. In the 22 specimens of I. the number varied from 

 3 to 15, but the difference, while to some extent perhaps due 

 to age and the size of the axial fossa, was mainly brought about 

 by the variations in size of the separate rods of the pali and 

 columella. Sections of the narrow base have a simple rod in 

 the columella, and as fresh rods arise on the trabeculae which 

 join the septa to this rod, there should be typically a gradual 

 increase, with increase in size of the calicles. In No. 30 there 

 was a tendency to twisting in the rods, but this was also visible 

 in Nos. 12, 27, and 38. Again, the depth of the rods in the axial 

 fossa varied from "5 to 6 mm. below the edge of the theca. 



The epitheca differed greatly, in some specimens giving their 

 external surface a glazed appearance, and in others allowing the 

 costae to be plainly visible almost to their bases of attachment. 



