38 



Sea thread coralline, Ellis' Coral., p. 21, pi. xii., no. 18, 

 a A. Sert. dichotoma, Ellis and Solander's Zooph., p. 48. 

 Turton's Lin,, vol. 4. p. 682. Stewart's Elem.. vol. 2, 

 p. 446. Campanularia dichotoma, Fleming's Brit. An., 

 p. 548. Grant's Comparative Anatomy, 10, fig. 5. Cyclop, 

 of Anatomy and Physiology, p. 108, fig. 30. Templelon 

 in Mag. Nat. Hist., vol. 9, p. 469. Laomedea dichotoma, 

 Lamouroux's Cor. Flex., p. 207. Johnston's Brit. Zooph., 

 p. 150, pi. 22, figs. 1 and 2, 



Hab. On stones from deep water, common; in pools 

 about low water mark ; in Whitsand bay, Looe, Polperro, 

 near Fowey, and Goran; common. On sponges, rare. 



It grows to the height of from six to ten inches, but is more 

 commonly about one. The appearance of this species is 

 confervoid. It is of a light transparent horn colour, rooted 

 bv minute tubular fibres; erect and dichotomously branched. 

 The cells are campannlate, biserial, on annulated footstalks a 

 little longer than the depth of the cell ; the apertures are 

 even and unarmed. The whole polypidom is divided into 

 long internodes, and the branches at their origin are an- 

 nulated, and those parts of the stem and branches which give 

 support to the cells are enlarged into kneed protuberances. 

 The vesicles are ovoid, or urn-shaped and axillary. The 

 ova are numerous and composed of two parts, a central dark 

 nucleus and a light surrounding zone. Beside this there are 

 some curious phenomena connected with the gemmules, 

 which are not mentioned here, because the nature and cha- 

 racter of them are exceedingly obscure: Sir J. G. Dalyell 

 has also noticed them, but not explained them; they are 

 therefore retained for further consideration. Ellis says it 

 ** seems most curiously contrived, from its structure, to resist 

 the violence of the waves, all its joints being furnished with 

 springs." 



KNOTTED SEA THREAD. Z. Geniculate. Short; 

 stem zig-zag, rarely branched; cells bell-shaped, alternate, 

 with an even rim, on ringed foot-stalks, standing on a 

 thickened joint of the stem. PI. x, 



Corallina confervoides gelatinosa alba, geniculis crassins- 

 culis pellucidis, Raii, Synnp. Stirp. vol. 1, p. 34 no. 7. Knotted 

 thread Coralline, Ellis' Coral., p. 22, pi. 12, no. 19, h'g. b B. 

 Sert. geniculata, Ellis and Solander's Zooph., p. 49. Tur- 

 ton's Lin., vol. 4, p. 682. Stewart's Elem., vol. 2, p. 446. 

 Campanularia geniculata, Fleming's Brit. An., p. 548. 

 Laomedea geniculata, Lamouroux's Cor. Flex., 208. Tem- 

 pleton in Mag. Nat. Hist., vol. 9, p. 466. Johnston's Brit. 

 Zooph., p. 151, pi. xxi., fi gs . i an( j 2. 



