OCR Text |
Show 420 PROF. J. A. THOMSON AND MR. W. D. HENDERSON ON [Apr. 10, A vertical section of the specimen showed numerous yellow with a diameter of 0*7 mm. SCLEROPHYTUM VIRIDE, sp. n. (Plate XXIX. figs. 2 k 3.) (1) This species is represented by numerous portions of very large colonies. Some of the colonies were a yard across ! In the living forms the general colour was bright green, the polyps were brown, the tentacles green. The stalk in one specimen is 34*5 m m . in height and in the other 30 mm. The portion of the crown is greatly folded and lobed, each of the larger lobes dividing into smaller lobes. In the majority the autozooids are completely retracted within the general ccenenchyma, but they are very numerous, especially towards the edge of the marginal lobe. The pores left by the retracted autozooids are variable in size, some 0*15 m m. x 0*1 mm., others 0*075 mm. x 0*075 mm., and others 0*1 x 0*075 m m . Their shape also varies from a circular opening to a somewhat oval-shaped pore. Between the openings of the autozooids lie the numerous very minute openings of the siphonozooids, becoming more numerous in proportion to the autozooids towards the central portion of the crown. The spicules are of three types :- (a) Long slender spindles with few rough wart-like tubercles, in length and breadth in millims. as follows :-0*45 x 0*06; 0*3x0*03; 0*2x0*025. (b) Short, thick, double clubs with a very short median waist and with whorls of rough wart-like tubercles which carry a number of small spines. They vary in length from 0*25-0*3 m m. and in breadth from 0*12-0*2 mm. (c) Small oval-shaped spicules with many tubercles as in (b), varying in length from 0*25-0*39 mm. and in breadth from 0*1-0*2 m m. The last type (c) may be a modification of (b) in which the free central portion has become obliterated. Among the first type (a) several show bifurcations at the ends. (2) In some other less contracted specimens the autozooids are numerous, up to 7 mm. in length including the tentacles, and are all marked by transverse annulations. On the tentacles the pinnules are arranged in one row on either side of the middle line on the oral surface; the number in a row varies from 10-14. The tentacles are short (about 1 mm.) in comparison to the polyps. The stomodaeum, which is greatly wrinkled, is 1*6 mm. in length. The siphonozooids are very numerous and small, giving the surface a pitted or dotted appearance. The spicules are of three types:- (a) Long slender spindles with very few and wart-like tubercles, from 0*2-0*3 mm. in Length and from 0*025-0*03 mm. in width. |