282 DESCRIPTION OF CHALK CORALS. 
had a considerable increase of dimensions, and a few were so far extended as to 
assume the character of lateral shoots, furnished in one case with conical pro- 
jections. The plan of growth was shown to a certain extent in the perfect ter- 
mination of a branch represented on a slightly enlarged scale by figure 6a. The 
greatest breadth of the fragment was rather more than half a line, that of a 
mature branch being about one line ; and the upper extremity consisted of a fasci- 
culus of tubes situated nearly in the axis of the branch, but inclined a little 
towards the observer’s right, the immediately subjacent projection bending to the 
left. By reference to figure 6 e, this position will be found to accord with that 
exhibited by an internal section, the centre of which is wholly tubular, and the 
fasciculi, springing entirely from that portion, diverge successively in opposite 
directions. ‘The difference between the breadth of the fragment and that of a 
mature branch proves also, that a certain amount of increase took place progress- 
ively without an alteration in the structures, marking a continued development 
in the coral, not by irregular outer additions as in Eschara and many other 
ascidian zoophytes, but by an augmentation of the constituents of the polype 
itself. 
The free portions of the fasciculi give a peculiar neatness of character to the 
front view of the branches (fig. 6a), and when examined in detail the variations 
were found to depend chiefly on the degree of preservation. The form was very 
generally conical, tapering in the best examples to a point, but occasionally 
cylindrical, accompanied however in those deviations with signs of irregular pro- 
duction ; and traces of a subdivision were detected in one case. Internally, the 
best-exhibited cones consisted wholly of tubes with a thin covering on the side 
facing the flat portion of the branch. The apertures were situated (fig. 6 ), with 
a few exceptions, on the back of the projections, and they were easily distinguished 
from the foramina by their size and other characters. The perfect mouths were 
inclined upwards or against the side of the cone, the direct opening being ob- 
liquely sloped downwards and outwards ; and the margin was smooth and formed 
of a solid substance similar to that of the general reticulation. For the greater 
part the apertures were not arranged uniformly, but occasionally a biserial dis- 
tribution occurred: in a few instances a single opening, or a greater number 
appeared in the network between adjacent cones ; and a lateral row was noticed 
near the base of an enlarged fasciculus or side shoot. 
The surface-structures of the front did not vary markedly to the extent ob- 
served, except towards the base, where the pores were much less distinct or 
