HYDROIDA. 
453 
brought thence by Mr. Hyndman are remarkably fine, their ordinary 
height being 9 inches ; some of them, too, branch profusely, so as to occupy 
nearly as much space in breadth as in height : — one specimen had at- 
tained the height of 12 inches. Nov., 1842, attached to Pecten maximus 
in Belfast market ; the shells stated to have been dredged in the Bay. 
W. T. 
T. Beanii, Johnst. 
Procured by dredging in Belfast Bay, where it in some situations seems 
to take the place of T. halecina. Before it was described as a distinct 
species, its peculiarities, independently of the remarkable ovaries, were 
noticed by Mr. Hyndman and myself ; its general aspect or habit first 
attracted our attention. Instead of the rigid “ herring bone ” appearance 
of T. halecina, it is somewhat flexible and graceful. Although not men- 
tioned in the description, this difference is observable in the plates of the 
British Zoophytes. 
, Among Zoophytes collected in Dublin Bay, by Prof. Harvey, in 1834, 
and kindly sent to me, were examples of this species. Adherent to 
oysters dredged at Killough, Co. Down. W. T. 
T. muricata , Johnst. 
For the only Irish specimen, a mere fragment of this Thoa which I 
have seen, I am indebted to Dr. Hassall, who found it near the Giant’s 
Causeway. W. T. 1842. 
Genus Sertularia. 
S. polyzonias , Linn. 
Dublin Bay, 1834, Prof. Harvey. Youghal, Miss Ball. Magilligan, Co. 
Londonderry, Mr. Hyndman. This is one of our most common Sertu- 
larice , on the coasts of Down and Antrim, and indeed those of Ireland 
generally ; it is usually attached to Algce and Zoophytes , more especially 
to Halidrys siliquosa and Flustra folia cea. The largest and finest speci- 
mens I have seen were from deep water, where, even on our northern 
coasts, they in more than one locality attained the magnitude mentioned 
by Templeton of 5 inches in height. See his description of S. pinnata. 
The Sertularia which commonly passes under the name of polyzonias in 
Ireland is the form figured in Ellis, and which is considered by M. Ed- 
wards distinct from the erect form represented on the same plate. He 
names the flexuous form S. Fllisii. 
All the specimens in my collection from various localities, whether 
growing in a flexuous or erect state, winding round the stem of Algae, or 
expanding in an arborescent form, with a single main stem (if it may so 
be called), have the cells with a toothed rim, and the vesicles toothed. 
I have not seen any vesicles with such an orifice as is represented in the 
erect form by Ellis, plate 2, fig. A. 
S. rugosa, Linn. 
On Flustra foliacea collected at Magilligan, Co. Londonderry, by Mr. 
Hyndman, 1838. On same species from Bootle coast, Liverpool, Mr. 
Henry Johnston, 1840 ; and on same, dredged at Sana Island, off the Mull 
f Cantire, Mr. Hyndman, 1841. 
S. rosacea , Linn. 
Dublin Bay, 1834, Prof. Harvey. April, 1835. 
