474 MR. H. N. MOSELEY ON THE STRUCTURE OF THE STYLASTERID2E. 
II. Family Stylasteridce (Gray). 
Corallum arborescent, with a strong tendency to assume a flabellar form, and to the 
development of the zooid pores on one face only of the flabellum, or on the lateral 
margins only of the branches composing it. In some genera a superficial layer only of 
the coral is living ; in others, nearly the entire mass retains its vitality. Pores with 
tabulae in two genera also. The gastropores usually provided with a conical calca- 
reous projection, “ style,” at their bases. In some genera, a rudimentary style 
present only in the dactylopores. Pores scattered irregularly, or grouped into more 
or less symmetrical systems, composed of a centrally-placed gastropore surrounded by 
a circlet of dactylopores. In some genera the mouths of the dactylopores appear as 
elongate chambers, disposed radially towards the centre of the gastropore into which 
they open, and the chambers being separated from one another only by thin partitions, 
“ pseudosepta the systems, “ cyclo-systems,” simulate closely calicles of Hexactinian 
corals. Nematocysts of two kinds, large and small, and of uniform shape in all the 
genera. Three-spined nematocysts absent. Gastrozooids cylindrical or flask-shaped 
in form always entirely retracted within the gastropores when at rest ; those of the 
former shape with from four to twelve tentacles, set in one whorl, and regular in 
number in all the gastrozooids in each species ; those of the latter devoid of tentacles. 
Bactylozooids simple elongate-conical bodies, devoid of tentacles, sometimes capable 
of entire retraction within the pores, sometimes not. Stocks of distinct sexes. Gono- 
phores adelocodonic, developed within sacs, “ gonangia,” which are contained within 
special cavities in the substance of the corallum, f ‘ ampullae.” Stocks of the two sexes 
alike in form as far as known, except in the size of the ampullae, which are larger and 
more prominent in the females. Ampullae containing in male stocks several gono- 
pliores; in female, in some genera, a single gonopliore, in others several. Spadix, in 
the female gonophores, cup-shaped, embracing a single ovum only, which becomes 
developed into a planula within the gonangium. 
Genus 1. Sporadopora, gen. nov., H. N. M. —Polypora* H. N. M. (Proc. Poy. Soc. 
No. 172, 1876, pp. 94, 95). — Corallum pure white, composed of finely reticular but 
compact coenenchym, forming stout vertical stems, usually compressed from before 
backwards, so as to be oval in transverse section. Stem giving off a limited number 
of irregularly dichotomous branches, which are flattened like it, and tend to coalesce 
by their lateral margins and assume a flabellate form, which is sometimes somewhat 
results as to tlie nature of Pocillopora , which is a Hexactinian. There can be no doubt that Seriatopora is 
closely allied to Pocillopora, and it is apparently by an oversight that Prof. Huxley has retained Pocillopora 
amongst the Millepores in his ‘ Manual of the Anatomy of Invertebrated Animals,’ London, 1877, p. 168. 
There seem to be no fossil genera, other than Millepora itself, which can with certainty be referred to the 
family. 
* I was kindly informed that Polypora was inadmissible, as being already in use by Mr, Etheridge, 
junr., F.G.S., &c. 
