REPORT ON THE ASTEROIDEA. 441 



arranged in nearly regular longitudinal lines, the median radial series beiDg larger than 

 those adjacent on each side. Between the median series and the adambulacral plates on 

 each side are three or four longitudinal series. The plates of the median radial series, 

 which imbricate slightly, are more or less convex or crested transversely, and each bears 

 three short, robust, cylindro-conical, obtusely tipped spinelets, the middle spinelets being 

 placed rather more adcentrally than their lateral companions. The surface of the plate is 

 covered with a close-fitting membrane, upon which are borne two or three small isolated 

 forcipiform pedicellarice. The plates of the most outward series are smaller, and bear 

 normally one spinelet, but two may be present near the base of the ray, accompanied by 

 one or two pedicellarise. These are succeeded by a second series of small plates similarly 

 armed with one spine, which alternate with the first series. Then follows a series of large 

 broader plates at the edge of the ray, which represent the supero-marginal plates ; each of 

 these bears two or three spinelets, one spine being placed on the middle of the plate and 

 another near the inferior end of the plate ; the latter appears somewhat isolated, and is 

 borne either on a prolongation of the plate or on a small intermediate plate, but I am 

 unable to state which without dissection. Two or three isolated, small, forcipiform pedicel- 

 larise occur on all the plates, and each of the series is separated by a longitudinal series of 

 single isolated papulae. Immediately external to the adambulacral plates, directly contin- 

 gent and not separated by any papulse, is a longitudinal series of small plates which 

 represent the infero-marginal plates. Each of these bears a short, compressed, almond- 

 shaped spinelet directed horizontally, forming a regular and conspicuous series of lateral 

 spines standing at the extreme margin of the ray. One or two smaller pedicellariae stand 

 at the base of this spine on the superior side. 



The adambulacral plates are very small. Their armature consists of two rather long, 

 cylindrical, slightly compressed, obtuse spinelets, placed one behind the other, and forming 

 two regular longitudinal rows. The outer series on the two sides of the ray are capable of 

 entirely closing the furrow, masking the inner series of spinelets and the tube-feet. 



The madreporiform body is small and circular, and appears to occupy the centre of a 

 rather large plate, the covering membrane of which terminates abruptly at the margin of 

 the madreporiform body. Its surface is grooved with comparatively few fine striations. 



The larger apical plates on the disk bear two or three spines similar to those on the 

 rays. A dorso-central, primary radials, basals, and under-basals, are distinguishable. 



The anal aperture is excentric. 



The ambulacral tube-feet, which are small and quadriserial in arrangement, have a 

 fleshy, button-like, terminal disk. 



Colour in alcohol, a light orange yellow. 



Locality. — 'Station 219. Off D'Entrecasteaux Eeef, North of the Admiralty Islands. 

 March 10, 1875. Lat. 1° 54' 0" S., long. 146° 39' 40" E. Depth 150 fathoms. Coral 

 mud. Surface temperature 84 o- Fahr. 



(ZOOL. CHALL. EXP. — PART LI. — 1888.) 56 



