OCR Text |
Show 1881.] THE SURVEY OF H.M.S. 'ALERT.' 93 the outermost of these rows, in which the spines are ordinarily arranged in pairs, and above by a row of, if any thing, shorter spines ; these are sometimes, towards the apex of the arm, arranged in pairs. On the dorsal face of the arm there are three sets of short spines, arranged irregularly in pairs, and extending along the arm; the median row is by far the most regular. The arms are five in number; but one was broken off from the specimen under description; of the four remaining two are white and two are black on their 1 1 1 dorsal surface; the rest of the creature is white, as are all the spines. The disk is exceedingly small and is but sparsely provided with spines; the radius of the disk is 14 millims., the length of the longest arm 70 millims. ; so that 22=5r. One specimen. Sandy Point, 9-10 fathoms; bottom, sand. ASTERIAS CUNNINGHAMI, Perrier. A. cunninghami, Perrier, Rev. Stell. 1875, p. 75; Ann. Nat. Hist. (4) xvii. p. 36. General appearance not unlike that of A. rubens. Arms five, elongated, gradually and regularly decreasing in width ; disk small ; madreporic plate obscure. A single row of adambulacral spines, flanked by a double longitudinal row of spines, every two being closely appressed ; the sides of the arms are occupied by a number of small tubercles. On the dorsal surface of the arms the tubercles are closely packed both towards the tip and the base, while they are much more sparse in the middle third of arm and on the central portion of the disk itself. Colour orange. 22 = 30, r = 8, therefore 22=3*75r. Breadth of arms at base 9 millims. Three perfect specimens, of which one is much smaller than the other two ; they are all smaller than the type specimen. Tom Bay, 0-30 fathoms; bottom, rock, kelp, and sand. ASTERIAS RUPICOLA (?). Asterias rupicola, Veirill, Bull. U.S. Nat. Museum, i. iii. p. 71. There are in the British Museum three specimens, which were collected by Dr. Cunningham, but to which no definite locality is attached ; these specimens I now, though with very considerable hesitation, assign to the Kerguelen form lately described by Prof. Verrill. The hesitation is not due to any insufficiency on the part of the description, which is by the hand of a master, but from the fact that in some points, such as the proportion of the greater and lesser radii and the breadth of the arms at their base, the specimens now in hand have the arms longer and more slender than those of Mr. Verrill's specimens. When, however, we take into account the appalling number of specific terms which have been applied to forms belonging to the genus Asterias, we shall, I think, act more wisely if we refrain from adding to these synonyms on the score of differences in character which may at some future time be shown to be due either |