468 Havpon— The Actiniaria of Torres Straits. 
is throughout of about the same thickness as the ectoderm of the proximal region of 
the tentacles. It presents no features worthy of special note. 
Disk.—The structure of the disk is similar to that of the proximal portion of 
the tentacles, no nematocysts, but numerous gland cells are present in the ectoderm. 
sophagus.—The ectoderm of the cesophagus is thrown into numerous (about 
24) folds. In the specimen of which I have transverse sections, there are three 
cesophageal grooves corresponding to the three pairs of directive mesenteries. 
Two of these grooves are close together, being separated by one pair of perfect 
between two pairs of imperfect mesenteries. 
Mesenteries.—The mesogloea is very thick in the peripheral portion of the 
mesenteries (Pl. xxx., fig. 4); the retractor muscles are very feebly developed. I 
have not noticed large nematocysts corresponding to those which occur so 
numerously in the endoderm of the mesenteries of C. viridis. 
The arrangement of the mesenteries is as follows :— 
D1, 2:58).4, 6,16) 7, 8,9: -D:—10, 1) 12.) Di 13114815, 16, t79018) 19,,20. 1235 
Thus there are three directives, and the intervals between them contain re- 
spectively 7, 1, and 6 pairs of mesenteries, and each interval also contains two 
pairs of imperfect mesenteries. The latter are usually on each side of the 
directives. Mr. Duerden and I have shown an analogous lack of symmetry in 
Corynactis Australis (Trans. R.D.S., vi, 1896, p. 153), and I find the same 
obtains in C. viridis, one specimen of which has the following arrangement :— 
D7, P8,5.960 7, 16.9, 10, 1, 19) D189 14 ed Gaal OOOO, eos: 
2h, 25, 26, 27, 28 = 30. 
With two directives only one groove is marked, and there is a decided asymmetry 
in the disposition of the mesenteries. 
Gonads.—None present in the specimen examined. 
Apparently all the species of Corynactis externally closely resemble one 
another, and curiously the 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 Philip, Australia (C. Australis), As has already been 
pointed out by Mr. Duerden and myself, the sphincter muscle differs in the 
various species, that of C. carnea, Studer, which lately has been described by 
Kwietniewski (Jenaische Zeitschr. xxx., p. 599, pl. xxvi., fig. 12), is somewhat 
similar to the sphincter of C. viridis. C. hoplites resembles C. Australis in possessing 
a thick mesoglcea in the body wall, and in the great thickness of the mesoglea 
in the proximal (7. e. outer) portions of the mesenteries. 
* In the above formula D = a pair of directive mesenteries, the upright numerals are pairs of perfect 
mesenteries and the italic numerals pairs of imperfect mesenteries. 
