402 PROF. J. A. THOMSON AND MR. W. D. HENDERSON ON [Apr. 10, 



Clavularia plava 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*7 5-1 mm. 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 mm. 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 mm. in length 

 by 0-8 mm. 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 slightlj'', 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 mm. 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 minu.te, smooth, 

 ovoid discs, 0-02 by 0-018 mm. 



Clavularia gracilis May. 



A small colony agrees with this species in having : 



(«) polyps of very diverse lengths, up to 20 mm, ; 



(b) short and thick piniaules in three iri-egular rows (some- 



times apparently in two rows) ; 



(c) no calcareous bodies ; 



{d) tentacles about 5 mm. 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 liave 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. 



