CLASSIFICATION OF ACTINIARIA joao 
Sub-tribe ENpomyaria. 14 families. Common characters or 
tendencies, 6 
1. Definite base save in one case (it may be somewhat reduced, or 
may form a float). 2. Basilar muscles usually present. 3. No 
mesogloeal sphincters (sphincter endodermal if present). 4. No 
acontia. 5. Secondary mesenteries exocoelic. 6. There may be 
no external complications of the body or tentacles, but verrucae, 
acrorhagi, vesicles, and complex tentacles are characteristic of different 
members of the group, more than one of them sometimes occurring 
in the same form; but there are no tentacles with basal mesogloeal 
swellings. 
Here there is often more than one tentacle on an endocoel, and there 
may be a good many on each main endo- and exocoel; or, on the other 
hand, there may be not more than one to each. 
The above lists show that even when one is dealing with 
larger groups it is generally possible to base them on a fair 
sum of characters or at least of tendencies. It should of course 
be remembered that each family has not only its own special 
family-features, as listed, in common, but also many of the 
group-characters behind the family. ‘To take a single example, 
the Actiniidae have in common 6 Actiniid characters + 6 
Endomyarian features + 7 Nynanthean characters + 6 Acti- 
niarian characters + 6 Dodecactiniarian characters + 9 Zo- 
anthactiniarian + 14 Anthozoan, not to mention all their 
Coelenterate and Metazoan points. So that they have, back 
to Anthozoa, 54 common characters—the number has to be 
reduced of course by any characters which may occur in more 
than one of the lists involved, or which may be inapplicable 
to the particular case in point, but even then the number will 
be considerable. 
5. EVoLuTIONARY SUGGESTIONS. 
That the classification suggested here has a firm foundation 
in character-summation will be evident from the above lists 
and the definitions later on; but it allows a certain amount 
of latitude for alternative ideas of evolutionary history, with 
which it is necessarily a good deal mixed up, especially in cases 
of large groups, where one is almost bound to think partly 
