524 T. A. STEPHENSON 
teristically thick body-walls, two siphonoglyphes, and numerous 
mesenteries, the older ones at least fertile and not much 
marked off from the others, many being perfect and their 
musculature not strong. The first family is the Halcuriidae 
sens. strict., the second the Actinernidae. 
§ H. 
The next five sections will deal with the ‘ Sea-Anemones ’ 
in the narrowest sense (i.e. such of them as were not dealt 
with in Part I), the usual forms, the majority-forms, exclusive 
of atypicals such as Athenaria and Endocoelactaria and the 
pre-Halcampid groups. 
§J. The family Actiniidae. 
This family, containing our commonest and most familiar 
anemones, has been the subject of a good deal of discussion 
and fluctuation. As it is usually understood at the moment, 
it is not much more homogeneous than the old group ‘ Parac- 
tidae ’, but contains three distinct types of mesenterial arrange- 
ment. Any discussion of it involves also the families Bolo- 
ceridae and Bunodidae, and these points will be dealt with 
in order. 
Firstly, the Actiniidae. If we consider the aggregate of 
genera usually included here—Actinia, Anemonia, Con- 
dylactis,Gyrostoma, Actinioides, Condylanthus, 
Myonanthus, Macrodactyla, and others, we find three 
types of mesenterial formula, as follows : 
(i) In Condylanthus the mesenteries are divided into 
macro- and microcnemes, the macrocnemes numbering six 
pairs (cf. Text-fig. 16, c). 
(i) In Myonanthus and Macrodactyla there is no 
division of mesenteries into macro- and microcnemes, but 
only six pairs are perfect (cf. Text-fig. 16, p). 
(iii) In the others there is no division of mesenteries into 
macro- and microcnemes, but there are numerous perfect 
mesenteries as a rule, always more than six pairs in adults 
(cf. Text-fig. 16, H, and Text-fig. 10). 
