290 Mr. 8. O. Ridley on Growth and Budding 
Represented by a single colony (fig. 1) and a detached 
branch, which has lived independently after its fracture from 
the parent specimen. They were collected and presented to the 
British Museum by Mr. H. O. Forbes, F.Z.S. &e., who has 
already (Proc. Roy. Geogr. Soc., Dec. 1879) described these 
islands, and with whose name I have much pleasure in asso- 
ciating this new type. The chief colony measures 83 millim. 
(34 inches) in height, 100 millim. (4 inches) in greatest 
breadth, and 55 millim. (24 inches) from front to back; the 
detached branch, which bifurcates three times, was about 
60 millim. long when alive. Parts of the corallum, owing 
either to an evanescent pigment or to traces of animal matter, 
have a most delicate pink tint. 
Some interesting points are brought out by the detached 
branch ; this occurs unrooted, but obviously had been broken 
off from the colony while yet alive (see fig. 4) and lived sub- 
sequently free. As commonly happens in such cases, the 
fractured surface has healed over; but in this case the new 
material is not a continuation of the superficial coenenchyma 
of the adjacent side over the stump, but the prolongation out- 
wards ot the loose central coenenchyma which has developed 
on itself five or six young calicles. Here also the law of 
centripetal gemmation asserts itself, these calicles occurring 
on the sides of a central cone of loose coenenchyma, of which 
the apex, 1 millim. long, is undifferentiated and bears no cali- 
cles. The same law is followed in the process of repair 
exhibited by a broken stump of a branch on the larger speci- 
men. The wide angle of bifurcation of the branches causes the 
colony to assume a low decumbent form, and bringing, as it does, 
neighbouring branches into juxtaposition, gives rise to ana- 
stomoses; the branching in various planes gives it a broad top. 
Bilateral Symmetry in the Madreporide.—In Madrepora 
elegans we have a decided bilaterality in the arrangement of 
the calicles on the corallum, a circumstance which has induced 
MM. Milne-Edwards and Haime to entertain the idea that 
this form might be generically distinct from Madrepora. No 
other Madreporidee exhibit this, so far as I am aware; bilatera- 
lity in the arrangement of the parts of the calicle is, how- 
ever, a prominent feature of a number of Madrepore, taking 
the form of a superior development of the upper and lower 
(distal and proximal) primary septa, sometimes carried to the 
extent of their union in the middle line at no great distance 
below their upper margins. In Montipora also. (at any rate, in 
digitata, Dana) the primaries are thus distinguished ; but here 
they are not always strictly upper and lower in relation to the 
long axis of the branches. This form of calicular bilaterality 
