REPORT ON THE ASTEROIDEA. 591 



space occupied by groups of large papula3 and numerous pedicellarise, which is bounded 

 superiorly by a single regular longitudinal row of short, robust, obtuse, equally spaced 

 spinelets borne on the representatives of the supero-marginal plates; and above these, 

 on the margin of the abactinal area, are numerous pedicellariae. 



The madreporiform body, which is small, sunken, and almost hidden by the encroach- 

 ment of the puffy membrane, is situated about midway between the centre of the disk and 

 the margin, and the tips of several obtuse, robust spinelets may be seen round the cir- 

 cumference. 



The ambulacral furrows are wide, and the tube-feet, which have a quadriserial arrange- 

 ment, are crowded, and have fleshy terminal disks with invaginated centres. ' 



Colour in alcohol, an ashy grey. 



Young Phase. — There is a small example from Port William, Falkland Islands, which 

 I take to be the young of this species. The dimensions are R = 15 "5 mm. ; r = 5 "25 mm. 

 The rays are well defined and of nearly uniform breadth from the base to the extremity. 

 There are not more than two or occasionally three spines in the oblique series on the infero- 

 marginal plates, and these come close up to the adambulacral plates. The intermediate 

 irregular series of spines noticed in the adult are not present in the young form, although 

 when three spinelets are present in the oblique series on the infero-marginal plates the 

 innermost one strikingly simulates in its position the intermediate spines referred to. 

 The supero-marginal series of spines is present, and pedicellariae are numerous and 

 relatively large. 



Localities. — In the Messier Channel, between "Wellington Island and the west coast of 

 Chili. January 1876. Exact position, depth, and conditions not recorded. 



Station 315. Port William, Falkland Islands. January 26, 1876. Lat. 51° 40' 0"S., 

 long. 57° 50' 0" W. Depth 5 to 10 fathoms. Sand, gravel. Surface temperature 50° - 

 Fahr. 



Remarks. — This species resembles Calvasterias antipodum in the length of the rays 

 and the general form, but differs by the absence of the crowded median radial line of 

 spinelets ("scale-like processes" of Bell 1 ), and by the presence of the regular and well- 

 developed series of supero-marginal spines, which are wanting in Calvasterias antipodum. 

 The arrangement of the spines on the infero-marginal plates and the presence of numerous 

 pedicellariae also serve to characterise Calvasterias stolidota. The general form and the 

 majority of the above-mentioned points of structure at once distinguish the species from 

 Calvasterias asterinoides. The young form, which is smaller in size than Calvasterias 

 asterinoides, is already distinguished by the well-developed rays, and has a facies alto- 

 gether different from that Asterina-shsiTped species. 



1 Proc. Zool. Soc. Lond., 1882, p. 122. 



