3 
In AeMepora the large nematocysts are oval or almost spherical in shape, and the 
long thread has a broad belt of thorns in the middle. In all the Stylasterina in which the 
large nematocysts have been found, their shape is much narrower and might be described as 
spindle-shaped; and, according to Mosgrey, the belt of thorns is at the base and not in the 
middle of the thread. As regards the smaller kind of nematocysts, the three-spined type so 
characteristic of M/zd/epora has not been found in any Stylasterid. 
The solid scalariform endoderm of the dactylozooids is another very distinctive feature 
of the family. In all the specimens of the genus J/7//efora that have been examined the 
dactylozooids show a cavity extending from the apex to the base and the endoderm cells are 
very similar to the endoderm cells lining the coenosarcal canals. The scalariform tissue is 
clearly a much more differentiated tissue than this and taken with other characters suggests 
that the Stylasterina are a more specialised group. 
The general characters of the gonophores of Stylasterina form another important point 
of difference from M/2llepora. The discovery of ampullae in a variety of AWzl/efora called MV. 
murraye by Quretcu') suggested that the gonophores might be similar to those of Stylaster; 
but the discovery by one of us”) that the ampullae bear medusae proved the error of this 
supposition. Whether the gonophores are or are not adelocodonic gonophores, as suggested 
by MoseLey, may be a matter open still to discussion but if they are they show features very 
different from those of any other adelocodonic gonophores in the Hydrozoa. The specialisation 
of the trophodisc in the female gonophore, whether we regard it as a modified manubrium 
or not, to purvey nourishment to the growing eggs is a definite and distinct character of 
the Stylasterina. 
Family StyLASTERIDAE 
with the characters of the order. 
Of the 14 genera of recent Stylasterids, Stylaster, Errina, Cryptohelia, Conopora and 
Distichopora are represented in the collection. The genera Allopora, Astylus, Sporadopora, 
Phalangopora, Pliobothrus, Labiopora and Spinifora are not represented in the collection. We 
consider that the genus Stexohefia is not distinct and should be merged with S¢y/aster and 
that the genus Lefzdofora (Pourtales) as pointed out by Mosetey, is not distinct and should 
be merged with Zrrzza. The genus Phalangofora (Kirkpatrick) *) differs from #yrzxa in the 
absence of a style in the gastropore but in other respects comes very close to it. A new 
genus S/eganopora is constituted for a fragment of a coral of very remarkable structure. 
Of the five genera represented in the collection Stylaster and Déstichopora occur in 
shallow water. St/aster extends from quite shallow water on the reefs into deep or very deep 
1) J. J. Quetcu, Challenger Reports, Vol. XVI. 
2) alae pen d's 
3) R. Kirkpatrick, Ann. de Mag. Nat. Hist. March 1887. 
