EEPORT ON THE ASTEROIDEA. 227 



interradial area is occupied by numerous small intermediate or ventral plates, all of which 

 bear croups of spinelets similar to those above mentioned ; and most of the plates in a 

 large specimen have a single flattened and pointed spinelet springing from the midst. 



The mouth-plates are elongate and ovoid, prominent, with a regular and conspicuous 

 armature, consisting of a single line of short, robust, papilliform spinelets, slightly flattened 

 and with rounded tops, arranged along the outer margin of the surface of the plate. The 

 space between the companion series of a mouth-angle is wide and elliptical in outline. On 

 the free side of the plate, and at a higher level, is a secondary series of small mouth-spines, 

 closely apposed to the bases of the superficial series, which fit into the interspaces, and are 

 almost invisible when viewed from above. The innermost mouth-spines are considerably 

 longer than the papilliform superficial armature, and form a small fan of four parallel spine- 

 lets at each mouth-angle, the outside spinelet at each side being shorter than the others. 



The madreporiform body is small, and situated rather nearer the margin than midway 

 between it and the centre of the disk. 



Colour in alcohol, yellowish grey, with traces of a darker grey tint remaining here and 

 there on the paxillar area. 



Locational Variation. — Two examples from Simon's Bay are of much larger size than 

 any of those which I have considered to be the type-form, and they are characterised by 

 the presence of a small appressed spine on the supero-marginal plates on the lateral wall of 

 the ray, near the rounding of the plate, and similar to the spines on the infero-marginal 

 plates. The spinelet is wanting on a few plates in the interbrachial arc, and at the 

 extremity of the ray. 



In a still larger specimen from Station 164, off Sydney, the rays are much broader and 

 flatter in appearance than in the examples above mentioned, and the supero-marginal 

 plates extend further on the abactinal surface, forming a comparatively broad border when 

 seen from above ; and the single, delicate, appressed spine borne on the supero-marginal 

 plates is even more elongate and conspicuous than in the specimens from Simon's Bay. 



It is interesting to note that the South African form is distinctly intermediate in size 

 and character between the New-Zealand and the Australian forms. Although the differ- 

 ences in appearance between the two latter are very striking when viewed by themselves, I 

 do not feel warranted under the circumstances, and with such a small supply of material at 

 command, in marking any of these distinctions by name. When more specimens are avail- 

 able, such a course may be found desirable. 



Localities. — Station 167. North-west of Port Hardy, New Zealand. June 24, 1874. 

 Lat. 39° 32' 0" S., long. 171° 48' 0" E. Depth 150 fathoms. Blue mud. Surface tem- 

 perature 58° '5 Fahr. 



Station 164. South-east of Sydney. June 12, 1874. Lat. 34° 8' 0" S., long. 

 152° 0' 0" E. Depth 950 fathoms. Green mud. Bottom temperature 36 0, 5 Fahr. ; 

 surface temperature 69° - 5 Fahr. 



