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Show 1906.] ALCYONARIANS FROM ZANZIBAR. 399 DESCRIPTION OF SPECIES. Order I. STOLONIFERA Hickson. Family C O R N U L A R I I D H E. Clavularia garcice Hickson. ,, garcice Hickson, var. inermis, nov. ,, flava May. ,, gracilis May. ,, reptans Hickson. „ strumosa Ehrenberg. „ margaritiferce Thomson k Henderson. ,, crosslandi, sp. n. ,, repens, sp. n. ,, pulchra, sp. n. ,, zanzibarensis, sp. n. ,, mollis, sp. n. ,, parvula, sp. n. ,, pregnans, sp. n. Sympodium punctatum May. ,, ccemdeum Ehrenberg. ,, fuscum, sp. n. ,, splendens, sp. n. CLAVULARIA. Note on the Genus. The problem of species in this genus is very difficult. The differences between species are within a narrow range, and many of the distinctions utilised, e. g. number of rows of pinnules, number in each row, seem to be too quantitative in character to be very satisfactory. Moreover, what seem to be well-marked species are connected by intermediate forms, and even in one colony there is sometimes considerable diversity. Let us give some illustrations. (a) To Clavularia garcice, of which Prof. Hickson had one specimen, we are inclined to refer several separate colonies. In some of these the pinnules vary from 13 to 30 on each side, yet the proportions, the general appearance, and the spicules seem identical. Some have one distinct row of pinnules, others have one row with an occasional simulation of two rows, others have two or three rows. Other specimens agree absolutely with some of these except that we could find no trace of spicules, though some members of the same colony showed a few scattered rods. (b) In specimens which agree well with C.fiava May, we found the pinnules in one row, in three rows, and in four rows; yet these forms were otherwise alike, showing, for instance, very minute ovoid spicules 0*02 in length by 0-015 in breadth. In another quite similar colony the spicules were rod-like-0'02 in length by 0*005 in breadth-and there were also some discs. |