CLASSIFICATION OF ACTINIARIA 523 
aberration, the Endocoelactids are sphincterless, and nearly 
always have spirocysts in the body-wall ectoderm. There is 
a definite base. The form of body and tentacles is variable, 
and may be ordinary, but the wall may be thick and heavy, 
the dise lobed, the tentacles often with aboral basal swellings. 
In fact we find here a tendency not found on the main line of 
Endomyaria (see p. 541, &¢.) or ‘ endodermal-sphinctered ’ 
anemones, towards a deep-water specialization similar to that 
which we found earlier on in certain Paractids and Actino- 
seyphids, &e. (see Part I). ‘Taking them as wholes, the Endo- 
coelactids are a set very different from average forms, being 
apparently a little Ime of evolution to themselves; and as 
such they should have slightly higher rank than that of a family, 
forming a group Endocoelactaria equal in level to the 
Athenaria. 
Carlgren includes Endocoelactids in his Protantheae along 
with Gonactiniidae and Ptychodactidae ; but since they seem 
evidently derived from a muscular Halcampaz-like ancestor 
with ciliated tracts, and have no ectodermal muscle in their 
body-walls, I cannot see the merit of that plan, or accept it. 
(See also pp. 541-2, 560, &c.) 
There are among the Endocoelactids two rather clearly 
marked out groups, one of them containing Halcurias 
and Carlgrenia, the other Actinernus and_ three 
_ related genera. The two groups seem to have fairly good 
claims to be regarded as families, and as such they are defined 
later on in this paper (Part III). There is in one of the families 
practically a division of the mesenteries into macro- and 
microcnemes (macrocnemes six to ten pairs, with circum- 
scribed retractors, gonads, and filaments; microcnemes 
confined to upper part of body except for four pairs of them 
in Carlgrenia—some of them may be perfect, but without 
retractor, gonad, or filament), and also there is constantly 
one siphonoglyphe only and no tendency to lobing of disc 
or tentacles. ‘These forms, especially Carlgrenia (Text-fig, 
16, G), are nearer their Halcampid ancestor than the others. 
In the other family we find the lobing tendency and charac- 
