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Show 1906.] ALCYONARIANS FROM ZANZIBAR. 437 Family VIRGULARIID^E. VIRGULARIA MIRABILIS Lamouroux, var. P E D U N C U L A T A Kolliker. The rachis is 172 m m . in length, but the upper part (for 51 mm.) consists of nothing but the axis, which tapers to a fine thread. The axis is 0*42 m m . in diameter, brownish in colour, and marked by a large number of parallel transverse stria?. Towards the upper end of the unweathered part of the rachis the transparent pinnules are very closely packed together and smaller than those on the lower part of the rachis. They are separated from one another by intervals of 0*8 mm., and vary in breadth from 0*9-1*05 m m . and in height from 0*6-0*7 m m. On each pinnule there are six or seven polyps in a single row. There is a clear streak on both rachidial surfaces of the rachis, but that on the prorachidial surface is slightly wider and has a groove running up the middle. The coenenchyma is thin and transparent, allowing the axis to shine through on both surfaces. Locality. Kokotoni, Zanzibar Island. In the mud at ordinary low-tide level. Previously recorded from Scandinavia, Denmark, Iceland, and Gulf of St. Lawrrence. VIRGULARIA MULTICALYCINA, sp. n. (Plate XXVI. figs. 4 k 5.) A well-preserved portion of a colony, probably near the tip. It has a light brown colour, and was described when living as " black and light drab." In a length of 22 millims. there are on each side 11 pinnules, each about 2*25 m m . in height, and bearing about 66 polyps in 2-4 rows. The breadth of the vane is 8 mm., that of the axis 1*35. On the prorachidial surface there is a bare streak 2*5 m m . in breadth, with a median longitudinal groove. At the insertion of each pinnule there is a superficial ramification of the nutritive canal, forming a characteristic pattern. The metarachidial surface has also a bare streak, but this is entirely hidden by the interlocking of the pinnules, which form a quite continuous covering over the wThole of that surface. Very characteristic is the undulatory curvature of the margin of the pinnule; the ends of the insertion are on about the same level on the prorachidial and metarachidial surfaces. The calices are very distinct, barrel-shaped with narrowed mouths and longitudinal ridges. A polyp with expanded tentacles is 1*25 m m . in length, the calyx occupying about 0*9 m m. On the prorachidial surface numerous minute zooids are to be seen, but no definite arrangement is recognisable. The shape of the axis is peculiar. The cross-section shows an irregular quadrilateral figure; the longest (metarachidial) side is 1*35 m m . in length and is slightly concave, the prorachidial side is 0*75 mm., and the two parachidial sides are slightly convex and about 0*75 m m . in length. On the surface of the axis there are longitudinally elongated elevations like interrupted ridges. This species resembles V. rumphii Kolliker in the close-set pinnules, in the crowded polyps, in the branching of the nutritive 2 9* |