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"Cellarinella dubia sp. nov.
(Pl. VIII, figs. 12a, b, and fig. 2 in text)
Fragments were found in the cotton wool of one of the jars, and probably they were derived from 623, though this is not quite certain, as the jar also contained 309 and 591.
Zoarium erect, compressed, with the two flatter surfaces slightly curved, and with zooecia on all four surfaces, with very large open pores or pits. On the anterior and dorsal surfaces there are two longitudinal rows of alternate zooecia while at the sides there is one row. Specimens from Cape Horn have the zoarium round.
On one or both sides of the aperture there is a raised avicularium, with an obtuse triangular mandible, and at the base of the avicularium a projection forms a kind of denticle, contracting the peristome, and giving it the appearance of a Schizoporellidan aperture. Where there is only one avicularium the peristomial aperture is unsymmetrical, as there is no denticle on the one side ; and in the few cases, where there is no avicularium, both denticles are wanting.
Larger pieces of this species were found in the spirit material from the Cape Horn Expedition, Dredge 4. Lat. 50º 25' S.- Long. 67º 36' W. ; 140 metres; +5.7 Centigrade, and from the zoarial growth it was at first taken for C. foveolata nov. In this specimen, from Cape Horn, the zoarium is cylindrical, and is attached by chitinous radicles. The older zooecia have large pores over the surface, while in the younger ones they are more pronounced round the borders ; and the slightly raised ovicells have radial slit-like pores, indicating its limits.
There is a second specimen from 177 Cape Horn Expedition, between l'île Navarin and l'île Hoste, 270 metres, +7.7 Centigrade. Some specimens in the British Museum, collected by DARWIN from Tierra del Fuego, and two others from the Straits of Magellan are this species, but the region round the aperture is striated or finely lined, and there are nearly always two avicularia.
Calcareous sections of the Cape Horn specimen, from the Paris Museum, are identical with those of C. foveolata nov. (Pl. V, fig. 2f).
HABITAT. — Off Patagonia, Lat. . 50° 52' 5.- Long. 67º 36' W.; 140 met. ; +5.7 C.; between the islands Navarin and Hoste 270 met.; +7.7 Cent.; Tierra del Fuego ; Straits of Magellan.
Exp. Antarct. Belge.
Probably from 623, Tangles VIII. Lat. 70º 00' S.- Long. 80º 48' W." (Waters, 1904: 58-9)