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



to any of the known species. The average length of the con- 

 tracted polyp is 5 mm. 



The tentacles are short and hUint, 1"8 mm. in length and 0"7 

 mm. in breadth. The pinnules practically cover the whole surface ; 

 they are very small and wart-like, and are arranged in 6-8 rows. 

 No calcareous bodies are to be seen, but there are abundant zoo- 

 chlorellfe with a diameter of 0*01 mm. Many of the polyps show 

 abundant ova. The colour in life was described as " pinkish 

 brown with blue tentacles." 



It may be unsatisfactory to establish a new species for speci- 

 mens which have so few positive characteristics ; it seems to us 

 the most workable way of finally arriving at a knowledge of the 

 relationships within this prolific genus. It must be left to some 

 one working on the spot to I'educe the number of species by dis- 

 covering the annectent forms. 



Locality. Near Kiungani, Zanzibar. 



Clavularia mollis, sp. n. 



The polyps of this rather puzzling form arise from a thin semi- 

 transparent membranous plate, 36 mm. long and 21 mm. in maxi- 

 mum width ; they seem to be crowded on the surface, l^ut when 

 separated considerable spaces are seen between their bases. They 

 are arranged in small groups of 4-8, which are joined together 

 for a short distance from their base by the fusion of their walls. 

 But each polyp can be traced to its origin, and does not lose itself in a 

 stalk-like poi'tion as in Xenia. Scattered between the groups small 

 single polyps may be seen. The polyps are capable of considerable 

 contraction, as some appeal- like small teat-shaped papilla; on the 

 sui'face of the basal membrane. The oral opening of the polyps is 

 small and pore-like, situated on the summit of a teat-like papilla. 

 The tentacles are short, with slender pinnules arranged all round. 

 The stomodfeiim is short, measuring only 0-9 mm. in length by 

 0'2 mm. in breadth in an adult polyp. 



There are numerous ova in most of the polyps. 



This species is also represented by a badly-preserved colony 

 40 mm, in length and 25 mm. in breadth. The stolon is smooth, 

 flat, and membranous. The polyps are 3 mm. in length, nearly 

 1-5 mm. in diameter, and are much contracted with numerous 

 annulations. The tentacles are nearly as long as the polyps 

 (2'7 mm.). The slender pinnules almost cover the tentacles, but 

 there is a bare aboral streak ; a common length is 0*5 mm. ; there 

 ai-e 6 rows of about 15 in each row. In the basal portions of the 

 polyps abundant ova are present. 



This form approaches in some ways May's C.jiava {non Hick- 

 son's C.flava), but the pinnules are thread-like instead of being 

 blunt, and there is no trace of spicules. 



Locality. Zanzibar shore. 



Clavularta parvula, sp. n. 



A colony spreading upon a ston(i, the individuals united partly 



