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Show 1906.] ALCYONARIANS FROM ZANZIBAR. 405 to the spicules :-(a) they occur in crowds on the ridges and these their white colour, and are also continued up the backs of the tentacles ; (b) they are irregular ovals like water-worn sand-grains; and (c) they are exceedingly minute, 0*01-0*02 in length by 0*005-0*01 in breadth. Locality. Zanzibar Channel, low water. CLAVULARIA REPENS, sp. n. This colony was found growing along with Hydroids on submerged stems of the marine phanerogram before mentioned. Its colour when living was reddish with brown polyps. The stolon consists of narrow strands. The polyps are from 4*5-5 mm. in length, with an oral diameter of 0*9-1 mm. They are narrower at the base. The tentacles are very short, only 0*4 mm. in length, with short pinnules arranged in one row on each side of the middle line. Each row consists of about 8 pinnules, and the two rows leave a very wide bare space on the aboral and a slightly narrower space on the oral surface of the tentacle. The specimen bears a strong superficial resemblance to C. margaritiferce Thomson k Henderson, but the spicules are entirely different. Here they consist of a continuous sheet of minute capstans (about0*03-0*05mm. in height and about0*02 in breadth) There are also some quadrangular forms with an axial cross (0*05x0*05). Locality. Common in Chuaka Bay. CLAVULARIA PULCHRA, sp. n. A membranous plate gives origin to numerous long polyps (23*5 x 3 mm.) with thin transparent walls. The tentacles 9 m m in length, are transparent and feathery, with the pinnules arranged in three rows on each side of the middle line, leaving a bare strip on the oral and also on the aboral surface The pinnules are long, cylindrical, and incurved, about 1*5 m m in length, usually 30 in a row. There are a few minute rod-like spicules 0*05 mm. in length and 0*007 mm. in breadth. The colour in spirit is white. In some respects this species approaches C. celebensis Hickson e. g. in the large number of the pinnules, and in the long polyps and tentacles. It differs in having a membranous stolon (as in Mays specimen), crowded polyps, thin polyp-walls (cf. May p. 44), much more substantial pinnules, and distinct spicules In another specimen it is worthy of note that the pinnules are tound in all stages of retraction, from 2 mm. in length to small wart-like projections. Locality. Zanzibar shore. CLAVULARIA ZANZIBARENSIS, sp. n. A dense crowd of short polyps arises from an irregular membrane spreading on nullipores. W e have been unable to refer it 27* |