456 Prof. P. M. Duncan and Mr. W. P. Sladen on 



may fairly, however, be regarded as a connecting link between 

 Asteracanthion and Stichaster. 



From the character of the ambulacral spines, the absence of 

 papula3, and the obscurity of the madreporiform body, we are 

 disposed to regard even the largest specimen we have as 

 being not yet fully developed : it measures 30 millims. in its 

 greatest diameter, and 5*5 millims. across the disk, and was 

 collected by Capt. Feilden in Discovery Bay. Depth 25 

 fathoms, hard bottom. Another individual from Cape Fraser 

 (80 fathoms) is only 10 millims. in greatest diameter, yet 

 presents all the characters of the larger specimen. 



Stichaster albulus (Stimps.), Verrill. 



Asteracanthion albulus, Stimpson, Invert. Grand Manan, p. 14, 



A. proble7na, Steenstrup, Vid. Meddel. 1854, p. 240 5 Liitken, Vid. Med- 



del. 1857, p. 30. ^ 

 Stichaster albulus, VerriU, Proc. Boston Soc. Nat. Hist. vol. x. 



Coll. Feilden : Franklin-Pierce Bay, 15 fathoms ; Proven, 

 13 fathoms. 



A little starfish with small disk and rounded or somewhat 

 arched rays, the number of which is almost invariably six, 

 three rays on one side being, as a rule, very much shorter 

 than those on the other. Proportion of the diameter of the 

 disk to that of the arms 1 : 5 or rather more. The ambu- 

 lacral furrows are wide, with suckers arranged in two simple 

 rows. On each interambulacral plate are two " ambulacral " 

 spines radiating slightly to the right and left. Closely succeeding 

 to those on the sides of the arms follow a series of three similar 

 spines, but not always a series opposite to each interambula- 

 cral plate, owing to the imbricating pieces being more widely 

 spaced. The dorsal ossicles present a regular rectangular 

 arrangement; and the interspaces, which are very small and 

 are occupied by a single papula, form, in consequence, regular 

 longitudinal and transverse rectilineal series. From each 

 intersection springs a small subquadrate group of from three 

 to five short dorsal spines, amongst which are placed one or 

 two pedicellarife. Towards the sides the pedicellarias are more 

 numerous. The spine groups are regularly disposed in longi- 

 tudinal and transverse lines, those of the middle row being 

 more densely packed than the others, thereby forming a more 

 or less distinct median line down each ray. The spinelets are 

 of equal length, and, being closely set, give a smooth velvety 

 appearance to the starfish. From the apices of the spinelets, 

 which are broader than the bases, proceed three or four small 

 denticles. 



Only three specimens of this Stichaster were obtained in 



