ZOOPHYTES. 
29 
Sertularia argentea , Ellis and Solander; Hincks, Brit. H. Z. 
vol. i. p. 268. 
Not common; from the deep-sea lines of the fishermen. 
This seems to be a form more characteristic of our southern 
shores. 
Sertularia cupressina , L.; Hincks, Brit. H. Z. vol. i. p. 270. 
Very plentiful in the coralline region—sometimes reaching 
the length of 18 inches. Besides the ordinary form there are 
two branched varieties. In the first, numerous secondary poly¬ 
paries spring from the ordinary dichotomous branches, each 
twig so burdened being very little thicker than the ordinary 
forms, and bearing in the usual manner for some distance the 
hydrothecge, which gradually become obsolete; this secondary 
trunk assumes considerable dimensions, with jointed stem and 
dichotomous branches, like an independent specimen. In the 
other variety the main stem itself splits into two divisions, or 
the secondary trunks throughout are directly connected there¬ 
with. 
Sertularia fusca , Johnst.; Hincks, Brit. H. Z. vol. i. p. 272. 
A single fine specimen only has yet been procured, in the 
deep water of the bay. Mr. Alder correctly observes that this 
form leads us to Thuiaria. 
Genus Hydrallmania, Hincks. 
Hy dr allmania falcata, L.; Hincks, Brit. H. Z. vol. i. p. 273. 
One of the most abundant hydroid zoophytes from the coral¬ 
line ground. Its form varies from the elongated spiral to the 
broadly branched condition; and it is frequently loaded with 
parasitic zoophytes, both horny and calcareous. It is a 
favourite site for Nudibranchiate Mollusca and their ova; and 
minute Annelids construct their tubes on every convenient 
bough. Young specimens are plentiful also under stones 
between tide-marks, where their habit differs considerably from 
the foregoing, having the form of a simple straight pinna, 
generally coated with parasitic structures, both animal and 
vegetable. 
