1906.] ALCYONARIANS FROM ZANZIBAR. 409 



stand. Between the larger meshes there are smaller ones on 

 which young polyps are seen. 



The polyjjsare about 5 mm. in length, with tentacles of I'S mm., 

 with about 8 slioi't pinnules in a single row on each side. On the 

 lower pai't of the polyp-body thei-e are no spicules, but just below 

 the base of the tentacles spicules become abundant, at fii'st 

 arranged transversely, then in more or less I'egulai- converging- 

 double rows running perpendicularly. There are also a few small 

 iiTegularly-disposed spicules in the tentacles. 



This species closely approaches Sym'podmm {Alcyoiiiimh) fulvum 

 Forsk., but dilFei-s in that the upper part of the polyp has 

 no transverse ring of spicules markedly different in size fi-om the 

 longitudinally-disposed spicules, in the presence of spicules on the 

 tentacles, and in other features. 



Localities. Wasin, Chuaka, Kiungani. Common. 



Sympodium splendens, sp. n. (Plate XXIX. fig. 8.) 



A beautifvd purplish-crimson colony, spreading around a mon- 

 axonid sponge. The sponge has a tubular form (probably due to 

 some foreign axis which has been lost). The basal membrane is 

 about 2 mm. in thickness ; the polyps occur irregularly, some- 

 times almost touching, elsewhere separated by intervals of 4 mm. 

 or so. A fully-extended polyp is 3-3*5 mm. in length ; the 

 tentacles extend for 2-2-3 mm. further; the average breadth of a 

 polyp is 1"75 mm. 



When the polyp is completely retracted we see a blunt conical 

 calyx (often 2*5 mm. in height), with 8 longitudinal ridges not 

 very sharply defined, and ending in 8 tiiangles. The whole is 

 purplish crimson, except at the summit, where a hint of the 

 yellowish - white polyp is seen. The fully- expanded polyp is 

 almost ti'ansparent, for the coloured spicules ai'e not continued 

 beyond the calyx. The flat tentacles have a broad bare sti'eak on 

 each surface ; there are two rows of pinnules on each side, 20-24 

 in each row. There is great variety in the spicules : — («) Straight 

 and curved spindles with prominent warts, usually few and distant, 

 sometimes fairly numerous (0'4 x 0'04, 0'35 x 0"03). (6) Irregular 

 forms: triradiate (0-175 x 0-15), quadradiate (0-2 x 0-125). 'The 

 great majority are purplish; others are transparent, with a con- 

 siderable organic residue, a few incline to red. 



Locality. Chuaka. 



Family Tubiporid^. 



TuBiPORA CHAMissoNis Ehrenberg. (= TuhijJora micsica Cha- 

 misso.) 



Locality. Large colonies ai-e abundant wherever coral gi'ows : 

 e. g., Prison Island and the reefs south of Zanzibar Harbour, 

 edge of eastern reef of Pemba. Not fovind at Chuaka, rare at 

 Wasin. 



