OCR Text |
Show 436 PROF. J. A. THOMSON AND MR. W. D. HENDERSON ON [Apr. 10, Ljocality. Station 12. Previously recorded from Zanzibar (Rousseau); Nossi Be in the Mozambique Channel, 10-12 fathoms (Keller). CO:LOGORGIA REPENS, sp. n. (Plate XXXI. fig. 1.) Several spreading colonies hardly exceeding 6 m m . in height. There are numerous polyps, in some groups of which it is impossible to distinguish the primary axial polyp from the others. The smallest polyps are mere papilla? 1*5 m m . in height, rising from a basal membrane; the longest project freely for 6-8 m m . An average breadth is about 1 m m . The surface is glistening white, and even to the naked eye appears rough and spicular. It is continuously covered with longitudinally disposed spindles. On the upper part of the polyps there are eight longitudinal ridges ending in triangular points, which bend inwards to form a kind of operculum over the inturned tentacles. Each ridge is composed of a double row of spicules, and the components of each row overlap so that there may be three abreast at any one place. In the lower part of the polyp the grooves between the ridges are sometimes prominent and bordered by pairs of spicules from the two adjacent ridges meeting like the letter V with the point downwards. In other cases the lower part of the polyp seems to be uniformly covered. The short and broad tentacles are completely inturned ; they bear about 6-8 rows of short conical pinnules (13-16 in a row) covering the whole of the oral surface. On the aboral surface there are numerous minute spicules arranged in chevron. The spicules of the general surface are spindles with irregular spines and warts. The following measurements were taken of length and breadth in millims.:-0*75 x 0*08 ; 0*7 x 0*05 ; 0*4 x 0*04. There can be but little doubt that these specimens represent young stages of colonies which have assumed an encrusting habit. They differ conspicuously from C. palmosa not only in the habit of growth, but in being rough and in having much larger spicules. Loccdity. Wasin. Section B. Pennatulacea. Family VlRGULARIID^E. Virgularia mirabilis Lamouroux, var. pedunculata Kolliker. ,, multicalycina, sp. 11. Family PENNATULIDX Subfamily PTEROEIDINVE. Pteroeides brachycaulon Kolliker. „ rigidum, sp. 11. ,, pidchellum, sp. n. |