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Show 50 ZOOLOGICAL COLLECTIONS M A D E DURING [J the lip. The lip undergoes great variations even in the same colony. In young colonies, and in some parts of old ones, the thickened ridge investing its edge is almost wanting. Again, it may appear from the front either as a straight line, as a two-horned ridge, or as a ridge produced mesially into a single point. The depth of the grooves of the surface also varies greatly, so that the surface appears either (i.) as beset with round, more or less elongated tubercles arranged round the median ridge, or (ii.) as grooved, the substance between the depressions not being thus divided into tubercles; in some specimens, too, the tuberculation itself is almost obliterated, apparently by thickening layers added from the exterior. As the grooved and tuberculated cells sometimes occur in the same colonies, it is probable that the latter (the only ones originally figured and described), being, as they are, particularly thick-walled specimens, are produced from the former by the thickening of the cell-wall and consequent greater or less obliteration of the spaces (the last stage in this process being the obliteration of the tubercles themselves), owing perhaps to age. {Cf. Hincks on the development of the zocecium, Hist. Brit. Mar. Polyzoa, p. 184, where he explains the origin and changes of the primary ridges and furrows.) Hab. Elizabeth Island, 6 fathoms, incrusting a mass of Balani and enveloping stem of Sertularia. Sandy Point, 7-10 fathoms, from large flexible worm-tube and Balanus on the same. RHYNCHOPORA BISPINOSA, Johnston. Lepralia bispinosa, Johnston, Brit. Zooph. (2) p. 326, pi. lvii. fig. 10. Rhynchopora bispinosa, Hincks, Hist. Brit. Mar. Polyz. p. 385, p. xl. fig. 1. Eschara unicornis, Hutton ?, Cat. Mar. Moll. N. Zealand, p. 99. To this species are referred with some doubt two colonies of Escha-roid form, consisting of narrow, strap-shaped branching growths, the branches not anastomosing. The denticle within the mouth is very small and sometimes absent; the suboral umbo is often somewhat eccentric, but usually high and truncate; there is sometimes a mound-like swelling bearing an avicularium on the opposite side of the mouth to the umbo ; the two supraoral spines are short and often stout; the surface is rough and regularly covered with large punctures and small avicularia (?) ; the cells are strongly convex and cover both sides of the fronds. Hab. Victoria Bank, off S.E. Brazil, 33 fathoms. LEPRALIA. Lepralia s. str. (as limited by Smitt and Hincks). LEPRALIA MONOCEROS, Busk, Cat. Polyz. Brit. Mus. p. 72, pi. xciii. figs. 5, 6. The punctures of the surface generally present a small tubercle |