PART I1.—ON HELIOPORIDA AND THEIR ALLIES. 
INTRODUCTION. 
THis Part is mainly a reprint of a memoir on the same subject which was published 
in the Philosophical Transactions for 1876 as a Preliminary Report on part of the 
results of the Challenger Expedition.‘ The matter has been, however, rearranged ; 
some new terms have been introduced, and the discussion of the results attained 
has been modified in order to be in accordance with the facts concerning the Hydro- 
corallinee which were ascertained by me since the paper was published. Certain 
parts of the original paper relating to the structure of Millepora, Stylaster, and 
Pocillopora have been omitted. 
I obtained specimens of the coral Heliopora caerulea in the living state at 
Samboangan, in the Island of Mindanao of the Philippine group, in January 1875. 
I examined the structure of the coral to some extent whilst in the fresh condition, 
and made a further detailed investigation of its anatomy during subsequent voyages. 
For comparison I studied the anatomy of a species of Sarcophyton dredged in 
shallow water amongst the reefs of the Admiralty Islands, and an account of the 
structure of this Aleyonarian is given here at some length. 
Very little had been written on the structure of Heliopora cerulea betore the first 
appearance of the present paper, and nothing further containing new information 
has been added since. The previous accounts referred only to the structure of 
the corallum or to the appearance of the living polyps, the latter being very 
imperfect and unsatisfactory. They are referred to as occasion requires in the body 
of the text, 
1 On the Structure and Relations of the Aleyonarian Heliopora cwrulea, with some Account of the Anatomy of a 
Species of Swrcophyton; Notes on the Structure of Species of the Genera Millepora, Pocillopora, and Stylaster ; and 
Remarks on the Affinities of certain Paleozoic Corals. By H. N. Moseley, M.A., Oxon., Naturalist to the Challenger 
Expedition (Phil. Trans. Roy. Soe., vol. clxvi. p. 91, part 1, 1876). 
