REPORT ON THE ASTEROIDEA. 69 
at once distinguish the form, and may ultimately entitle it to be ranked as a distinct 
species, are the greater number of supero-marginal plates, the narrowness of the rays, the 
character of the spinulation of the actinal interradial areas, the absence of pedicellariz 
alike on this area and on the abactinal area, and finally the character of the adambulacral 
armature. The madreporiform body appears to be somewhat smaller. 
Locality.—Station 133. In the South Atlantic, west of the island of Tristan 
da Cunha. October 11, 1873. Lat. 35° 41’ 0” S., long. 20° 55’ 0” W. Depth 1900 
fathoms. Globigerina ooze. Bottom temperature 35°'4 Fahr.; surface temperature 58°-0 
Fahr. 
2b. Dytaster exilis, var. carinata, nov. 
a feature further 
This variety is characterised by the high and strongly keeled rays 
emphasised by their narrowness. The paxillze upon the disk are comparatively large and 
distinct, and composed of rather robust but low papilliform spinelets, whilst along the ray 
the paxillee become extremely small, and seldom have more than three to five papillz in 
each. ‘There are very numerous valvate pedicellarize along the margin of the abactinal 
area of the ray, and also some upon the disk. In the type-form there are no pedicellarize 
on the abactinal area. The actinal interradial areas have numerous very large well- 
developed pedicellariz irregularly arranged; the individual intermediate plates which 
cover the area are quite indistinguishable, and they bear small skin-covered papilliform 
granules. In the armature of the adambulacral plates the spines of the furrow series are 
large and thick, compressed transversely ; those of the second series are rather wide apart, 
not more than five or six being present ; they are dagger-shaped, compressed longitudinally, 
and are nearly as long as the furrow series. External to them is a row, sometimes two, 
of small papilliform spinelets or granules. The solitary enlarged spinelet in the second 
series of spines on the adambulacral plates is confined quite to the tip of the ray, where 
it is thick and stumpy. The madreporiform body is remarkably large, and with very 
coarse paxillz upon it. There are forty-two or forty-three supero-marginal plates. The 
measurements are R= 98 mm.; r= 16°5 mm. 
Young Phase.—A small example taken at the same station seems to me to belong with 
little doubt to this form. The dimensions are R= 11°5 mm.; r=3'75 mm. Its general 
appearance at first glance is very different from that of the adult, its facies and propor- 
tions resembling those of Astropecten. There is as yet no indication of the narrow carinate 
rays of the adult, There are eleven supero-marginal plates between the median interradial 
line and the terminal plate. These extend well upon the abactinal surface, their breadth 
being equal to, or even slightly greater than, their length, and they form a well-defined 
border to the abactinal surface as seen from above, the breadth a little beyond the middle 
of the ray being nearly as great as that of the intermediate paxillar area. The margins 
of the ray are well rounded. The surface of the plates is covered with small, rather widely 
