OCR Text |
Show 418 PROF. J. A. THOMSON AND MR. W. D. HENDERSON ON [Apr. 10, thick coating of large spicules, either lying on, or protruding the surface, many reaching a length of 6 m m. On the capitulum, which is thin with incurved edges, the autozooids appeal- usually in small groups of twos or threes. Each group is generally elevated on a small protuberance, or each auto-zooid may have a slight elevation of its own. On the edge of the capitulum the autozooids are more numerous, and they do not occur in groups nor are they raised above the general surface. The spicules are of two distinct types-(1) large spindles, either straight or slightly curved, closely covered with small, rough, wart-like projections; and (2) small spicules which vary from spindles to rods, with rough prominent projections, which often cluster more closely at one end, thus giving a club-shaped appearance. Their measurements are as follows:- (1) Length varies from 1-4*6 m m . and the breadth from 0*15- 0*55 m m. (2) Length varies from 0*1-0*5 m m . and breadth from 0*03- 0*075 m m. Loccdity. Wasin, 10 fathoms. SCLEROPHYTUM POLYDACTYLUM Dana. (Plate XXXI. fig. 2.) A complete specimen 75*5 m m . in height. The lower part of the stalk is very rigid, with spicules readily visible to the naked eye. The upper part is marked by longitudinal grooves and folds, and is devoid of the larger spicules which are present in the lower part. The capitulum is divided into a large number of small, blunt, finger-like lobes, on which the autozooids seem to be almost equally distributed. The numerous small autozooids are almost all completely retracted, a few can be seen with the tentacles appearing above the surface. The tentacles are short (0*6 mm.) and thick, with the pinnules arranged in one row on either side of the middle line of the oral surface. The eleven pairs of pinnules are small, cylindrical, and rather blunt. The spicules : I. Of the upper part of stem :- (a) Large straight or curved spindles covered with many rough tubercles, varying from 0*6-2*7 m m . in length and from 0*15-0*5 m m . in breadth. (b) Small straight or irregularly-shaped spicules with large rough spines, varying in length from 0*1-0*35 m m . and in width from 0*02-0*09 m m. (c) Straight spicules with very few smooth spines, varying in length from 0*2-0*7 m m . and in width from 0*075-0*15 m m. They often show slight traces of four rays, and these show a X-marking at the junction of the rays. II. Of the lower part of the stalk :- The same types of spicules are present, but there is a marked predominance of (a). They are more varied here and often show |