190 THE VOYAGE OF H.M.S. CHALLENGER. 
Alveopora retusa, Verrill. 
Alveopora retusa, Verrill, Bull. Mus. Comp. Zo]. Cambridge, U.S.A., i. p. 43. 
A single small specimen, on which an abundantly developed pellicular epitheca is 
present, was obtained. The growth of the upper portion of the main lobe of the 
specimen has been disturbed, evidently owing to injury caused by some foreign body which 
has settled upon it, the position of which can easily be seen. On this lobe, and especially 
on its basal portion, the cells are rather small and shallow, with thickened, irregular, 
spiniform septa, which are seldom more than twelve in number, while the wall is 
irregularly fenestrate and thickened, and spinulose at its free edge. On a smaller basal 
lobe the typical structure of the species is more clearly seen, but the characteristic third 
cycle is not complete. 
Locality.—Somerset, Cape York, 5 fathoms. 
HYDROCORALLINAs. 
Family MILLEporip&. 
Genus Millepora, Linneeus. 
Millepora (pars), Linnzus, Syst. Nat., ed. 10, p. 790. 
5 Milne-Edwards and Haime, Cor., iii, p. 225. 
* Moseley, Zool. Chall. Exp., pt. vil. p. 18. 
Through the researches of Professor Moseley, who has confirmed and extended the 
observations of Louis Agassiz as to the hydroid nature of the Milleporide, we have an 
accurate knowledge of the structure and affinities of Millepora. By the discovery of 
ampullee* on the new species, Millepora murrayi, I have been able to give additional 
confirmation to the opinion of Professor Moseley on the classification of Millepora. The 
ampulla, which are described under Millepora murrayi, do not seem to differ in any 
marked particular from those of the Stylasteride. 
Hight species of the genus were obtained. 
1. Millepora alcicornis, Linneeus. 
Millepora alcicornis, Linneus, Syst. Nat., ed. 10, p. 791. 
i. 3 Dana, Zoophytes, p. 543. 
Three specimens of this species were obtained. One, from Bermuda, consists of a 
very large, curved, flabellate ccenosteum, formed by numerous very coalescent branches 
1 Nature, 1884, p. 539, 
