OCR Text |
Show 402 PROF. J. A. THOMSON AND MR. W. D. HENDERSON ON [Apr. 10, CLAVULARIA FLAVA May {non Hickson). (Plate XXX. fig. 4.) Four small pieces of a light brown colour appear to be referable to this species. The basal membrane is soft and about 1 mm. in thickness, and bears crowded polyps. The polyps are substantial, marked by annulations and also by longitudinal furrows, 3-4 mm. in length by 0*75-1 m m . in breadth, with lanceolate tentacles fully 3 mm. in length, with acute ends. The pinnules are very short and blunt, arranged in four rows on each side, usually 17 in a row. The spicules are densely crowded, extremely minute, smooth oval discs, about 0*02 mm. in length and 0*015 m m. in breadth. Prof. Hickson speaks of the spicules of C. garcice as the smallest he had seen, but these are much smaller. Locality. Zanzibar shore, low tide among coral. Previously recorded from Zanzibar. In another clump, growing on a monocotyledonous twig, the polyps are usually 9 mm. in length by 1-1*5 mm. in breadth and are longitudinally ridged. The tentacles are 3-3*2 m m. in length by 0*8 m m . in breadth, with the pinnules arranged in three rows on either side of the middle line. The pinnules, many of which are slightly clavate at the tip, leave a long bare space on the aboral surface which extends the whole length of the tentacle and tapers slightly, but on the oral surface the bare space is very wide at the base, narrows quickly, and becomes almost linear for the greater part of the length of the tentacle. The pinnules are from 0*18-0*25 mm. in length by 0*13 mm. in breadth. Abundant ova were present in the lower part of the polyps. The spicules are small rod-like bodies 0*02 mm. in length and 0'005 m m . in breadth, and there were also some discs. In another colony spreading on Millepora some of the polyps showed only one row of pinnules on each side, while contracted forms showed three. The spicules were very minute, smooth, ovoid discs, 0*02 by 0*018 m m. CLAVULARIA GRACILIS May. A small colony agrees with this species in having : (a) polyps of very diverse lengths, up to 20 mm.; (b) short and thick pinnules in three irregular rows (sometimes apparently in two rows); (c) no calcareous bodies ; (d) tentacles about 5 m m . in length. There is no funnel-like expansion * at the top of the polyp as was frequently observed by May; the bare streak on each side of * From what we have seen in C. pregnans, sp. n., we are inclined to suggest that these expansions, noted by various authors in different species, may be reproductive enlargements. |