300 THE VOYAGE OF H.MS. CHALLENGER. 
diameter only very slightly greater than the longitudinal ; and in the outer two series the 
difference is still smaller, whilst the respective diameters in the outermost series are almost 
equal. The tabula of the three lateral series of paxille bear fourteen to sixteen of the 
marginal prismatic spinelets, and four to eight of the semiglobular granules in the enclosed 
area. Most of the paxille of the median series bear one of the large entrenched pedi- 
cellarize similar to those above described, which extends across the major diameter of 
the tabulum ; and here and there a paxilla of the lateral series is similarly provided. 
The interradial areas are nearly equilaterally triangular in outline, the base extending 
along seven or eight of the supero-marginal plates in the interbrachial arc; they are 
covered with small subrhomboid plates compactly placed in lines parallel to the longi- 
tudinal series of the radial areas, and are beset with small, uniform, semiglobular granules 
similar to those on the supero-marginal plates; some of these plates are also furnished 
with pedicellarize, but they are few and far between. The converging lines of plates do 
not form any abrupt indication of the median interradial line. 
The primary embryonic plates are clearly discernible, the primary radials and basal 
plates being larger than the other paxille ; a plate representing the under-basal is also to be 
distinguished, and this is frequently separated from the primary radial by a pair of inter- 
mediate plates; one or more series of intermediate plates intervene between the above- 
mentioned primary plates and the dorso-central, which is a little larger. The anal 
aperture lies external to this plate, opposite the postero-lateral interradium. The madre- 
poriform body is small and slightly convex, and is placed external to the adjacent basal 
plate, its position on the disk being about one-fifth of the distance from the centre to the 
extreme margin. 
Colour in alcohol, yellowish white. 
Localities.—Station 204. Off Tablas Island, Philippine group. November 2, 1874. 
Lat. 12° 43’ 0” N., long. 122° 9’ 0” E. Depth 100 to 115 fathoms. Green mud. 
Surface temperature 84°-0 Fahr. 
Station 188. In the Arafura Sea, near the entrance to Torres Straits. September 
10, 1874. Lat. 9° 59’ 0” S., long. 189° 42’ 0” E. Depth 28 fathoms. Green mud. 
Surface temperature 78°°5 Fahr. 
Remarks.—Nymphaster symbolicus is readily distinguished from Nymphaster pro- 
tentus and its allies by the tabulate and paxilliform character of the radial abactinal 
plates, by the presence of a medio-radial series of plates, which separate the two opposite 
series of supero-marginal plates throughout the ray, and by the presence of large entrenched 
pedicellarize of a remarkable form. 
la. Nymphaster symbolicus, var. breviradiata, nov. 
A variety of Nymphaster symbolicus occurs at Station 192. The form is of smaller 
size, but the rays are comparatively a little wider and shorter. The paxille of the 
