Happon—The Actiniaria of Torres Straits. 465 
is given in my diagnosis of the genus: a reference to Pl. xxx., fig. 5, will make 
this more clearly understood. It will be noticed that the section figured in 
Pl. xxx., fig. 6, passing through one pair of directives; the two elements of this 
pair, like all the other pairs of mesenteries are widely separated peripherally, but 
are close to the neighbouring element of the adjoining pair of imperfect 
mesenteries. In every case the associated perfect and imperfect mesenteries are 
attached to the bottom of one of the twenty sulci that longitudinally furrow the 
column. ‘Two associated mesenteries are seen on a larger scale in Pl. xxx., fig. 7; 
and a very characteristic form taken by the retractor muscle of one of the 
perfect mesenteries is seen in Pl. xxx., fig. 8; the mesogleeal plaits are very 
fine, slightly branched, and few in number. 
All the tissues of the body are thin, the general appearance of the ectoderm 
and endoderm is shown in Pl. xxx., figs. 9, 10, which also illustrate the very 
simple character of the endodermal sphincter muscle. So far as I can see, the 
mesenterial filaments have a very simple character (PI. xxx., fig. 11). No gonads 
are present. 
The float consists of vesicular layers of a cuticular secretion of the pedal disk; 
associated with it I find a large number of filaments which evidently belong to 
an Alga. 
Order II.—STICHODACTYLIN, Andr. 
Hexactiniz with two kinds of tentacles, the main tentacles at the margin of 
the oral disk and accessory tentacles arranged radially in rows or groups on the 
oral disk. Numerous tentacles may communicate with one endocel. ‘Tentacles 
either similar or varied in form. 
CoraLLImorPHIDZ, . . Corallimorphus, Corynactis. 
DiscosoMIp&, . . Discosomoides, Discosoma, Radianthus, Stoichactis. 
RHODACTIDA, . . Rhodactis, Actinotryx, Ricordea, Heteranthus. 
THALASSIANTHIDZ, . . Cryptodendrum, Heterodactyla, Actineria, Thalas- 
sianthus. 
ACTINODENDRIDZ, . . Actinodendron, Megalactis, Acremodactyla. 
PHYMANTHID&, . . Phymanthus, Thelaceros. 
Family.—Coratiimorpnipm, Hertwig, 1882. 
Stichodactyline with a marginal corona of tentacles, and accessory tentacles 
similar to those of the margin arranged in radial series, each series consisting of 
from one to many tentacles. Musculature throughout weak. 
This family was constituted by Hertwig (1882, p. 21) to include the genus 
TRANS. ROY. DUB. SOC., N.S. YOL. VI., PART XVI. CDN 
