412 Happon—The Actiniaria of Torres Straits. 
in pairs and radially, appearing almost simultaneously in all the intermesenterial 
spaces. ‘The longitudinal (retractor) muscles of each pair are on the faces which 
look towards each other; that is, towards the intramesenterial spaces, except in 
the case of two (occasionally one or more than two) pairs, the directives, in which 
the longitudinal muscles are on the faces which look away from each other; that 
is, are turned towards the adjacent intermesenterial spaces. 
This, with very slight modifications, is the definition given by M*Murrich 
(1893, p. 140). Toa somewhat similar definition, Carlgren adds :—‘‘ Body-wall and 
cesophagus without ectodermal, longitudinal, muscular, and ganglionic layers.” 
This statement is very generally true; but I am not yet convinced that it is 
universally so, at least as far as the muscle fibres are concerned. Hertwig’s 
Monaulez and Paractiniz are now included in this tribe. 
Order I.—ACTINIINA, M. Edw., 1857. 
Hexactinie with simple, similar tentacles, situated at the periphery of the oral 
disk, the central portion of which is bare. Only one tentacle communicates with 
each intramesenterial chamber (endoccel). 
This order, or sub-tribe, is adopted by Andres, M*Murrich, Carlgren, and 
others. 
Family.—Ityanruipm, Gosse, 1858; cf. Carlgren, 1893, p. 36. 
Actiniinze with the aboral extremity of the body rounded, and without a pedal 
disk. 
I have adopted Carlgren’s definition, which is certainly wide enough ; there is 
no need to repeat his discussion of the group. 
Sub-Fam.—Hatcampiya, Kwietn., 1896 (= Haleampomorphine, Carlgren, 1893). 
HALCAMPA, Gosse. 
Ilyanthide with six pairs of perfect mesenteries; body divided into capitulum, 
scapus, and physa; sphincter diffuse, endodermal, or absent; twelve tentacles. 
Kwietniewski finds that Halcampa purpurea, Studer, has no sphincter. He says : 
‘‘vyon einem entodermalen Ringmuskel kann eigentlich nicht die Rede sein. Ebenso 
gut fehlt auch ein mesodermaler Sphincter” (p. 588). I have recently cut fresh 
sections of Haleampa chrysanthellum and of H. arenarea; in neither can I find any 
trace of a mesogleeal sphincter; but I do find a very feeble diffuse endodermal 
sphincter, which is slightly more developed in the latter species; but this may be 
due to its being a larger polyp. 
