CHAP. IV.] ST. THOMAS TO BERMUDAS. 253 
septa, are seen to be arranged with considerable regularity in 
radiating rows, which mark out a series of successive lines fol- 
lowing the course of the margins of the septa, and representing 
their lines of growth. 
The columella is about 4 mm. in diameter, and is composed 
of a number of contorted lamine, finely granulated, and more 
or less fused together in the older individuals. 
The extreme diameter of the largest specimen, measured 
from the outer edges of the exsert septa, is 32mm. The height 
of the calicle is 16 mm.; total height to the top of the septa, 20 
mm.; diameter of the base of the calicle, 21 mm.; of circlet of 
basal spines, 28 mm. This is a very marked and handsome cor- 
al. Fresh specimens are of a pure white color, and the crown- 
like shape is very elegant. 
Thirteen specimens were procured of another pretty coral 
belonging to the Turbinolidee — Deltocyathus Agassizii, Pour- 
TALES (Fig. 63). This species has been also described and fig- 
ured by Pourtales.* 
Fic. 63.—Deltocyathus Agassizii, PourTaLKs, x4. (No. 24.) 
Our specimens vary in diameter from 4 to 13 mm. Dr. 
Martin Duncan considers this species identical with D. /talicus, 
and the distinctions between the two species seem very critical. 
M. de Pourtales considers that the recent differs from the fossil 
* Toe. cit., p. 14. 
Il.—17 
