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THE VOYAGE OF H.M.S. CHALLENGER. 
(1) Tubucellciria opuntioides, Pallas (PL XXIV. fig. 7, and PI. XXXVI. fig. 19, pars). 
Cellularia opuntioides, Pallas, Elench., p. 61, 1766. 
Sertularia opuntioides, Gmelin, 1789. 
Cellaria cereoides (pars), Lamx., Lamk. 
Tubucellaria opuntioides (pars), d’Orb. 
Character. — Zoarium 1 to 2 inches high, forming tufted growths ( fruticuli inconditi, 
Pallas) ; ramification irregular, sometimes ternate, rarely opposite ; segments short or 
rather thick. Zooecia distinct, pyriform, tapering above gradually into the tubular peris- 
tome, which curves gently forwards, slightly dilated towards the circular orifice, and 
grooved longitudinally, each groove containing a series of angular punctures ; the intervening 
ridges finely beaded. Surface (calcined) reticulato-scrobiculate, the bottom of the pits 
being formed by a delicate centrally perforated calcareous diaphragm ; interstitial ridges 
finely beaded. Operculum (PI. XXXVI. fig. 19) in the form of a rounded oblong dish- 
cover, with the convexity outwards and a thickened border or rim. The opening measuring 
from 0 ,/ -006 to ‘008 x 0"-003 to -004. 
Habitat. — St. Paul’s Rocks, North Atlantic ; shallow water. 
[John Adam’s Bank, Voy. of H.M.S. “Herald.”] 
This well marked form agrees so perfectly with Pallas’ admirably graphic description 
that I have no doubt of its being the species he intended, notwithstanding the difference 
of locality. Nor can there be any doubt of its distinction from the Mediterranean or 
may be also North Atlantic form described by Dr. Solander ; nor again from a form 
which I have provisionally regarded as most probably that intended by d’Orbigny under 
the name “ fusiformis,” of which, if I am right, a fine specimen exists in the British 
Museum (No. 82, 2, 23, 410), from Thursday Island, Torres Strait, but of which I possess 
only one or two imperfect fragments from Australia or South Africa, but which suffice to 
show that the operculum is identical, or nearly so, with that of Tubucellaria opuntioides, 
from which facts we may consider the two to be closely related though differing widely in 
habit. The operculum also in Tubucellaria cereoides, it should be remarked, though of 
the same peculiar dish-cover-like conformation, is quite distinct. 
(2) Tubucellaria hirsuta, Lamouroux (PL XXXVI. fig. 18). 
Cellaria liirsuta, Lamx., Hist, des Polyp., p. 126, pi. ii. fig. 4, 1816. 
Cellaria barbata, Lamk. 
Cellaria and Tubucellaria barbata, d’Orb. 
Onchopora hirsuta, Busk. 
Tubucellaria hirsuta, Macgillivray, Decade v. p. 52, pi. xlix. fig. 6. 
Character. — Zoarium 2 to 3 inches high, composed of tolerably uniform, short, 
thickish internodes articulated dichotomously. Zooecia distinct, convex, slender, pyriform, 
much attenuated downwards, and above gradually tapering into the slender tubular 
