EEPOET ON THE ASTEROIDEA. 5 7 'J 



series on each plate. The spinelets are equal in length, slightly compressed, broad, chisel- 

 shaped, and truncate at the tip. 



Immediately external to the adambulacral plates follows a series of actinal (1 infero- 

 marginal) plates, upon which are borne four spinelets, closely placed at the base, radiating 

 slightly apart, forming a very oblicpie series upon the plate, the base line being at an 

 angle of 45° to the margin of the furrow ; these spinelets are equal, broad, more compressed 

 than those on the adambulacral plates, slightly flaring, chisel-shaped, and truncate at the 

 tip. No pedicellariae are associated either with these spinelets, or with those forming the 

 armature of the adambulacral plates. This series of actinal (? infero-marginal) plates is 

 separated from the next above by a narrow space in which papulae are present. The suc- 

 ceeding series, which is perhaps the representative of a series of supero-marginal plates, 

 forms a regular longitudinal line, and the spinulation of the plates is precisely similar to 

 that on the abactinal plates generally, excepting that a single spinelet near the inferior 

 edge of each plate is a trifle longer and is flattened, truncate and chisel-shaped at the tip, 

 simulating in miniature the chisel-shaped spines on the actinal and adambulacral plates. 

 This single spine on each plate forms a regular series along the ray, but is so small that 

 it is scarcely noticeable without a magnifying-glass. 



The madreporiform body, which is remarkably small and situated near the margin at 

 the summit of the almost vertical interbrachial arc, is surrounded by a closely packed 

 circlet of rounded papilliform spinelets. It is elliptical or circular in shape, and the 

 surface, which is slightly concave, is grooved with fine radiating striations. 



Colour in alcohol, greyish white, with traces of a purplish colour on the abactinal sur- 

 face in the case of a large example. In a smaller specimen the purple colour is more fully 

 preserved. 



Localities. — Off Marion Island. Depth 50 fathoms. 



Station 151. Off Heard Island. February 7, 1874. Lat, 52° 59' 3D" 8., long. 

 73° 33' 30" E. Depth 75 fathoms. Volcanic mud. Surface temperature 36°'2 Fahr. 



Remarks. — This species is distinguished by the transverse series of three flattened 

 spinelets on the adambulacral plates, and by the presence of the remarkable obliquely 

 placed combs of four flattened spinelets on the infero-marginal plates. The character of 

 the abactinal plating and spinulation is also characteristic, and produces a habit distinctly 

 different from that of any other species except Asterias (Smilastcrias) triremis. 



13. Asterias (Smilasterias) triremis, n. sp. (PI. CI. figs. 5 and 6 ; PI. CII. figs. 5 and ti). 



Pays five. Pt = 35 mm. ; r = 5'5 mm. R >6 r. Breadth of a ray at the base about 

 7 mm. 



Pays elongate, tapering, convex, and apparently subcylindrical abactinally, but flattened 

 actinally. Disk small and convex, often more or less tumid and higher than the base of 

 the rays. Interbrachial arcs acute. 



