Havpon—The Actiniaria of Torres Straits. 409 
EPIZOANTHUS, Gray, 1867. (Not recorded from Torres Straits. ) 
Macrocnemic Zoanthez, with a single mesogloeal sphincter muscle. The body- 
wall is incrusted. The ectoderm is usually continuous, but may be discontinuous ; 
cell-islets in the mesogleea. Dicecious polyps, connected by ccenenchyme, which 
may be band-like, incrusting, or greatly reduced, as in the free form. 
Platyzoanthus mussoides, Saville-Kent, 1893; ‘‘The Great Barrier Reef of Aus- 
tralia,” p. 155, with figure. 
It is unfortunate that Mr. Saville-Kent has allowed his enthusiasm for novel- 
ties to run away with his discretion, and at the same time to indulge in the 
reprehensible practice of publishing new genera and species without diagnosing 
them. A glance at the outline sketch given by the author is sufficient to show 
that the supposed new type is no Zoanthean at all. The description is too imper- 
fect to allow of certainty of identification, but the form is probably a species of 
Actinotryx (cf. p. 480). 
I have brought my earlier studies on the Torres Straits Zoantheze up to date, 
and for the sake of convenience I have retained the original order. Taking the 
mesenteries into consideration, the Brachycneminze may be regarded as slightly 
more primitive than the Macrocnemine ; on the other hand Parazoanthus has the 
simplest sphincter muscle and Zoanthus the most complex ; this would, therefore, 
reyerse the order given above. If we regard the Brachyenemine as haying 
retained the more primitive arrangement of the mesenteries, then the mesoglceal 
position of the sphincter muscle has been independently arrived at in the two 
groups. One genus (Parazoanthus) of the higher group (Macrocnemine) having 
retained the primitive diffuse endodermal sphincter, while one genus (Zoanthus) 
of the lower group (Brachycneminz) has acquired a double mesoglceal sphincter. 
I would call attention to two recent papers—one by Mr. Duerden and myself 
(Trans. R. D. S., 1896, p. 139), in which five new species of Zoanthez are de- 
scribed, and the other by Mr. Duerden (Trans. R. D. 8., 1898, p. 329)—in which 
he deals with the Zoanthez of Jamaica. 
Tribe IV.—PROTACTINIA (M*Murrich, 1891) = PROTANTHEA 
(Carlgren, 1891). 
Actiniaria ‘“‘ with twelve primary mesenteries; with one, or a pair, or two 
pairs of secondary mesenteries on each side of the sagittal axis, the increase in 
number of the secondary mesenteries occurring from the dorsal towards the 
ventral side.” (M*Murrich, 1891: ‘“* The Phylogeny of the Actinozoa,” p. 161. ) 
“* Anthozoa, with twelve primary mesenteries, of which eight at least are 
perfect, and which are arranged in pairs; the longitudinal mesenteries of each 
TRANS. ROY. DUBL. SOC., N.S. , VOL. VI., PART XVI. 8P 
