416 Happon—The Actiniaria of Torres Straits. 
it would be hazardous to suggest that this is a uniformly ascending series, as it is 
conceivable, though perhaps not probable, that a sphincter might degenerate. 
There is a peculiar difficulty in defining the different genera of this family ; 
and I cannot hope that the following arrangement will prove final, though it fairly 
well expresses the present state of our knowledge. 
The family contains the following genera :— 
Actinia. Bolocera. 
Anemonia, Polystomidium. 
Condylactis. Macrodactyla. 
Antheopsis. Myonanthus. 
Actinioides. Antheomorphe. 
ACTINIA, Browne. 
Actiniidee with smooth column ; capitular margin with large, conspicuous, often 
brightly-coloured marginal spherules (acrorhagi) which may or may not be furnished 
with a well-developed battery of nematocysts; tentacles usually rather short; a 
a broad diffuse endodermal sphincter. 
Although, according to Andres (p. 392), Patrick Browne, in 1756, was the first 
to employ the term Actinia, the genus with its type species was recognisably 
defined by Linnzeus (1766-68, p. 1088), and has been adopted ever since. 
The following four species can with certainty be allocated to this genus :— 
A. equina, . Linn. 1768, p. 1088 (= A. mesembryanthemum, Ell. and Sol. 1786, 
p- 4); Gosse, 1860, p. 175; Andr. 1884, p. 182, Simon, 
1892, p. 42. 
A. cari, . . D.Ch. 1825, pp. 238, 243; Andr. 1884, p. 187. 
A. infecunda, . MM. 1893, p. 146 (n. n. for Comactis flagellifera, Hertw. 1882, 
p- 32, not of Dana). 
A. citrina, . . (Hadd. and Shackl.) 1893, p. 125. 
Actinia citrina (H. & S.). 
(PIS, figs. 1, 22 el exUNOV IE ees slo) 
Anemonia citrina, Hadd. and Shack]. 1893; Proce. R.D.S. vit, p. 125. 
Form.—Column soft, produced above into a parapet of well-defined spherules ; 
oral disk round when young; margin folded in large specimens, feebly and imper- 
fectly retractile; mouth round, slightly raised, no cesophageal furrows visible ; 
tentacles of moderate length, thin uniform calibre, in three rows, from one to two 
hundred in number. 
