KEPOKT ON THE ASTEROIDEA. 35 



voluted, their general disposition having the appearance of radiating from a central point. 

 A numher of the larger paxillre surround the margin of the madreporite. 



The papula? 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 o- Fahr. ; surface temperature 40°"5 Fahr. 



Remarks. — This species is nearly related to Pontaster tenuispinus, 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 tenuispinus, 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 pedicellarise. The paxillae of the disk-area are smaller 

 than in examples of Pontaster tenuispinus 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 = ll'5 mm. R > 5 r. Breadth of a ray between the 

 second and third supero-marginal plates, 10 mm. A larger example measures E = 73 mm. ; 

 r = 13'25 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 arcs 

 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 paxillce of the abactinal surface are rather small and distinctly spaced, but do not 

 diminish in size along the rays so much as in Pontaster tenuispinus, and consequently 

 appear larger than in that form. The larger paxilla? 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 paxillse on the 



