470 MR. H. N. MOSELEY ON THE STRUCTURE OE THE STYLASTERID2E. 
made in a paper “ On the Structure of Millepora in the Phil. Trans., Yol. 167, Pt. I., 
1877, p. 132. The placing of the two families together seems justified in the present 
stage of knowledge concerning them ; but the Milleporidae, in the general form of their 
zooids, seem allied to the gymnoblastic Hydroids, whereas the presence of distinct 
gonangia in the Stylasteridae seems to ally these latter to the calypto bias tic group. 
Ampullae seem certainly to be absent in Milleporidae, and their gonophores are, there- 
fore, probably developed free of the coralliun. Further research may lead to the 
separation of the two families. The characters of the sub-order Hydrocorallinae and of 
the families Milleporidae and Stylasteridae are given in the sequel in a concise tabular 
form, and also in a series of more extended and comprehensive statements in which no 
known detail of importance is omitted. 
The components of the family Stylasteridae have hitherto been classified from a 
knowledge of the structure of the coralliun alone, and even this has been but imper- 
fectly investigated in most instances ; further, the descriptions given of the genera 
and species have been distorted by the violent efforts made by naturalists to discover 
septa and interseptal chambers in the so-called calicles of these supposed anthozoan 
corals. 
The descriptions of the genera at least thus required to be rewritten, and modified 
according to the present knowledge of the structure of the members of the family. 
This has been attempted in the sequel where the characters of the genera given 
embrace those derived from the structures of the soft tissues as well as of the hard. 
Unfortunately, the soft structures are known in only one species in almost all the 
genera, and in almost all in but one sex. Hence the classification here given will 
doubtless need subsequent modification. It merely professes to be an attempt to 
define the genera in the best manner now possible. 
In the case of two genera, Distichopora and Labiopora, nothing is known of the soft 
structures. Four new genera — Sporadopora , Labiopora, Spinipora, and Astylus — are 
’'described. Count de Pourtales’ genus Lepidopora is merged in Errina, from which, 
in the absence of information concerning the soft structures, it can hardly be con- 
sidered distinct. The lid-like coverings of the gastropores, by the presence of which 
the genus Lepidopora is distinguished, are most frequently composed of fused dacty- 
lopore projections, and do not consist of special elevations of the margins of the 
gastropore mouths themselves. Although this latter is sometimes the case, Errina 
labiata, a new species of which the structure is described in the present paper, 
seems to form a gradation between the species described as of the genus Lepidopora 
and Errina aspera. Count de Pourtales originally placed his Lepidoporas under the 
genus Errina. 
Cyclopora (Verrill) and Stenohelia (Kent) are further omitted from the list. The 
latter was formed to include Allopora Madeirensis, which seems to come very near to 
Astylus and Cryptohelia in that it has the cyclo-systems all directed towards one face 
of the flabellum ; but the presence of a style in the gastropores is decisive in excluding 
