REPORT ON THE ASTEROIDEA. 35 
voluted, their general disposition having the appearance of radiating from a central point. 
A number of the larger paxilla surround the margin of the madreporite. 
The papule are confined to an oval or pyriform area at the base of each ray ; they are 
of small size, and probably from forty to fifty are contained in each papularium. 
Colour in alcohol, a bleached yellowish ashy white, frequently with a pinkish shade 
on the abactinal paxillar area. 
Locality—Station 49. South of Halifax, Nova Scotia. May 20, 1873. Lat. 
43° 3’ 0” N., long. 63° 39’ 0” W. Depth 85 fathoms. Gravel, stones. Bottom tempera- 
ture 35°°0 Fahr. ; surface temperature 40°°5 Fahr. 
Remarks.—This species is nearly related to Pontaster tenwispinus, but presents a 
number of differences whose constancy and character appear to justify the recognition of 
the form as a distinct species rather than as a mere locational variety. When compared 
with Pontaster tenwspinus, Pontaster hebitus is distinguished by the comparatively small 
disk; by the rays being generally broader throughout and devoid of any rapid expansion 
at the base; by the greater breadth of the supero-marginal plates on the abactinal sur- 
face ; by the robust but short and truncate spines on the marginal and adambulacral 
plates ; by the character of the armature of the adambulacral plates, and by the total 
absence therefrom of the two-jawed pedicellariz. The paxillz of the disk-area are smaller 
than in examples of Pontaster tenwispinus of the same dimensions, and the general habit 
of Pontaster hebitus is larger and much more robust. Notwithstanding these differences, 
it is unquestionable that the species are very closely allied, and are most probably repre- 
sentative forms derived directly from a common ancestry. 
4, Pontaster limbatus, n. sp. (Pl. VI. figs. 3 and 4; Pl. VII. figs. 1 and 2). 
Rays five R=59 mm.; r=11'5 mm. R>5r._ Breadth of a ray between the 
second and third supero-marginal plates,.10 mm. A larger example measures R= 73 mm.; 
y=1325 mm. Breadth at the same place, 12 mm. 
Rays moderately elongate, tapering gradually and regularly from the base, which is 
broad, to a finely pointed and attenuate extremity. Disk small. Interbrachial ares 
wide but rather angular. Lateral walls high and vertical. Marginal plates forming a 
broad and slightly raised border on the abactinal surface. Abactinal surface of disk and 
rays flat. Actinal surface slightly convex on the disk, and more so along the rays, which 
have the appearance of being well rounded at the margins. 
The paxille of the abactinal surface are rather small and distinctly spaced, but do not 
diminish in size along the rays so much as in Pontaster tenwispinus, and consequently 
appear larger than in that form. The larger paxille on the disk are composed of very 
small, short, papilliform spinelets, which usually take the form of a more or less compact 
group, rather than of a circlet surrounding the tabulum. Very few of the paxille on the 
