430 Happon—The Actiniaria of Torres Straits. 
B. Kerguelensis, Stud. 1878, 544; Andr. 1884, p. 206; M°M. 1893, p. 155; 
Kwiet., 1896, p. 592. 
B multicornis, Verr. 1879, p. 198; Andr. 1884, p. 237; MM. 1898, p. 155. 
B. multiporum, (Hertw.) 1882, p. 129; 1888, p. 17 (Liponema multiporum, Hertw.) ; 
MM. 1893, p. 209. 
B. longicornis, Carlgr. 1891, p. 241; 1893, p. 50. 
B. occidua, M°M. 1893, p. 154. 
B. pannosa, M°M. 1893, p. 156. 
B. brevicornis, MM. 1898, p. 158. 
It is possible, as M*Murrich has pointed out (1893, p. 153), that Danielssen’s 
new genus and species, Sideractis glacialis (1890, p. 14) is a species of Bolocera. 
Unfortunately Danielssen’s description is too vague to be of much value; we 
cannot even be sure of the nature of the sphincter muscle. The chief character 
appears to be that the tentacles are multiples of 8 (8 + 8 + 16), and that there are 16 
perfect and 16 imperfect mesenteries. 
POLYSTOMIDIUM, Hertw., 1882, p. 67. 
Actiniide, with a_smooth, but longitudinally, furrowed column; capitular 
margin crenulated, with a space between the margin and the tentacular corona ; 
tentacles deciduous; circular muscle endodermal. 
I have recast the definition of this genus, as Hertwig describes the crenula- 
tions of the capitular margin as “ marginal spherules.’’? There is little doubt that 
acrorhagi have developed from such ‘small knobs”; but I do not think we can 
regard these as true marginal spherules. Hertwig’s phrase, ‘‘ tentacles transformed 
by retrograde formation into stomidia,” has been replaced by ‘‘ tentacles decidu- 
ous,” as probably being more correct. 
This genus appears to be very closely allied to Bolocera; as the tentacles have 
not been described, we do not know whether they possess the sphincter muscle 
characteristic of Bolocera. Gosse describes the ‘ margin (of the column of 
Bolocera eques) as forming a thick parapet, the summit obtusely edged, and notched 
with close-set denticulations,” a condition which is not very dissimilar to that 
figured by Hertwig for Polystomidium. Slight longitudinal furrows have also 
been noted in some species of Bolocera. Hertwig himself admits that ‘in their 
habit of body, in the endodermal position of the circular muscle, and in the 
presence of the marginal spherules, these animals are allied to the Antheade.” I 
am of opinion that this genus should be merged with Bolocera. 
P. patens, Hertw., 1882, p. 67. 
