OCR Text |
Show 406 PROF. J. A. THOMSON AND MR, W. D. HENDERSON ON [Apr. 10, to any of the known species. The average length of the contracted polyp is 5 m m. The tentacles are short and blunt, 1*8 m m . in length and 0*7 m m . in breadth. The pinnules practically cover the whole surface ; they are very small and wart-like, and are arranged in 6-8 rows. N o calcareous bodies are to be seen, but there are abundant zoo-chlorellre with a diameter of 0*01 m m . 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 specimens 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 reduce the number of species by discovering 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 m m . long and 21 m m . in maxim u m width ; they seem to be crowded on the surface, but 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 portion as in Xenia. Scattered between the groups small single polyps may be seen. The polyps are capable of considerable contraction, as some appear like small teat-shaped papillae on the surface 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 stomoda3iim is short, measuring only 0*9 m m . in length by 0*2 m m . 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 m m , in length and 25 m m . in breadth. The stolon is smooth, flat, and membranous. The polyps are 3 m m . in length, nearly 1*5 m m . 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 are 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.ffava (nonJELick-son's C.flava), but the pinnules are thread-like instead of being blunt, and there is no trace of spicules. Locality. Zanzibar shore. CLAVULARIA PARVULA, sp. n. A colony spreading upon a stone, the individuals united partly |