410 Havpon—The Actiniaria of Torres Straits. 
pair being on the faces of the mesenteries which are turned towards the intra- 
mesenterial space, except in the case of two pairs, the directives, situated at the 
extremities of the sagittal axis of the stomatodeeum, whose longitudinal muscles 
are on the faces of the mesenteries which look towards the adjacent intermesen- 
terial space. In addition to these primary mesenteries, secondary mesenteries 
are also present; of these there may be one on each side, situated in the suleulo- 
lateral intermesenterial space, or a pair on each side in the same intermesenterial 
space, or two pairs on each side in the sulculo-lateral and lateral intermesenterial 
spaces. The development of the mesenteries is upon a bilateral plan.” (M°Mur- 
rich,1893, p. 137.) 
‘“‘ Actiniaria, with paired mesentaries, arranged according to the Hexactinian 
plan. Body-wall and cesophagus with ectodermal ganglionic—and muscular— 
layers.” (Carlgren, 1893, p. 23.) 
Carlgren and M*Murrich proposed the names Protantheze and Protactiniz 
respectively for a new tribe of Actiniaria about the same time, and included more 
or less the same forms. Later (1893, p. 136) Carlgren thus criticises the defin1- 
tion of M*Murrich, which I have just given. ‘It appears to me that the 
characters which M*Murrich has given to it are not good, and do not well diffe- 
rentiate the Protactiniz from the Halcampidee.” 
The points at issue appear to be these :— 
M*Murrich emphasises the arrangements of the mesenteries in Scytophorus, 
Gonactinia, and Oractis, and regards the series of gradually increasing complexity 
as exhibited in these genera respectively as of prime importance; although, as a 
matter of fact Scytophorus is a somewhat divergent type. 
Carlgren rather dismisses these as phases of the Hexactinian type; doubtless 
he would willingly admit their probable phylogenetic significance, but he was 
struck with what he considers to be a more fundamental character in the forms 
he more particularly studied, which is the possession of nervous and muscular 
layers by the ectoderm of the body-wall and cesophagus. This is an undoubtedly 
ancestral character which has been transmitted from the Scyphistoma-like 
ancestor, and it is this that Carlgren makes of prime importance in his diagnosis. 
So impressed is Carlgren with the value of this character that wherever it 
occurs he would place that form within this tribe. [lor example, ectodermal 
muscles oceur in the body-wall of Corallimorphus and of Corynactis—thus he 
makes the Corallimorphide (= Corynactide) a family of the Protantheze. When I 
was preparing for the press a joint Paper with Mr. Duerden, ‘‘On some Actini- 
aria from Australia and other Districts” (Trans. R. D. 8. vr, 1896), on my own 
authority and without consulting Mr. Duerden, I adopted this classification of 
Dr. Carlgren’s. On the whole I prefer to retain the older view which places that 
family among the Stichodactylinz. 
