Part I1.—Stichodactyline and Zoanthee. 181 
Genus.—CORYNACTIS, Allman. 
Corynactis, . Allman, 1846; Johnson, 1847; Milne-Edwards, 1857 ; Gosse, 
1860; Andres, 1883; Hertwig, 1888 ; Haddon, 1898. 
Draytonia, . Duchassaing and Michelotti, 1866. 
Corallimorphide, in which the column-wall is smooth, tentacles knobbed, 
arranged in several cycles and in radiating rows, the outer larger than the inner. 
Tentacles and mesenteries generally tetramerous. Gonidial grooves present or 
absent. An ectodermal longitudinal muscular layer on the column-wall and on the 
stomodeeal wall ; endodermal sphincter muscle very weak. Mesenterial filaments 
devoid of ciliated streak. Mesogloea practically homogeneous. 
All the representatives of the genus are small polyps, and the descriptions 
of the various species given by the older writers refer only to the external 
features. The most salient of these are the knobbed tentacles, and the com- 
munication of more than one witha mesenterial space. In the present species, 
and in @. wiridis, they are tetramerous, but in @. carnea, Stud., according to 
Kwietniewski’s (1898) observations, the mesenteries appear to be hexamerous. 
Professor Hertwig (1888) was the first to make a histological examination 
of any member of the genus, and to discover the presence of longitudinal muscle 
fibres on the outer side of the body-wall. Professor Haddon and myself (1896, 
p. 152) found the same in C. australis, and Haddon (1898, p. 467) in C. hoplites. 
MM. Duchassaing and Michelotti erected the genus Draytonia for the species 
about to be described, distinguishing it from Corynactis on account of the circle 
of green spots upon the capitulum and disc. In the specimens which I have 
examined, the pigment spots do not project above the smooth surface, and those 
on the column cannot be in any way regarded as acrorhagi, and may or may 
not be present. They are certainly not deserving of generic distinction. 
Haddon (1898, p. 468) refers to the curious fact that an ‘ emerald green ring 
round the capitulum is characteristic of forms so widely distributed as European 
Seas (C. viridis), off the coast of Buenos Ayres (C. carnea), and Port Phillip, Australia 
(C. australis).” In the present instance the ring is represented by a circle of spots 
of the same colour. 
Corynactis myrcia (Duchassaing and Michelotti). 
(elxere tO Felco gw le xa foso—o) Plaxy.. 1g. 3.) 
Draytona myreia, . Duchassaing and Michelotti, 1866, p. 124, pl i1., fig. 8. 
Corynactis myrcia, . Andres, 1883, p. 485. 
The base is spreading, and in diameter larger than the column. It is irregular 
TRANS. ROY. DUB, SOC., N.S VOL. VII., PART YI, 2D 
