1906.] ALCYONARIANS FROM ZANZIBAR. 405 



to the spicules : — (a) they occur in crowds on the ridges and give 

 these their white colour, and are also continued up the backs 

 of the tentacles ; (6) 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. 



Olavularia repens, sp. n. 



This colony was found growing along Avith Hydroids on 

 submerged stems of the marine phanerogram before mentioned. 

 Its colour when living was reddish with broAvn polyps. The 

 stolon consists of narrow strands. 



The polyps are from 4-5-5 mm. in length, with an oral diameter 

 of O'9-l 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 verj^ wide bare space on the aboral and a slightly narrower 

 space on the oral surface of the tentacle. 



The specimen bears a strong supei'ficial resemblance to C. 

 margaritiferce Thomson & Henderson, but the spicules are entirely 

 different. Here they consist of a continuous sheet of minute 

 capstans (about 0'03-0"05 mm. in height and aboutO-02 in breadth). 

 There are also some quadrangular forms with an axial cross 

 (0-05 X 0-05). 



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 mm. 

 in length, ai-e 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 mm. 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. celehe^isis 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 

 May's 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 

 found in all stages of retraction, fi'om 2 mm. in length to small 

 wart-like projections. 



Locality. Zai:izibar shore. 



Clavularia zanzibarensis, sp. n. 



A dense crowd of short polj^s arises from an irregular mem- 

 brane spreading on nullipores. We have been unable to refer it 



27* 



