REPORT ON THE ASTEROIDEA. 423 



Colour in alcohol, a bleached greyish white. 



Locality. — Station 218. Off the north coast of New Guinea, south-west of the 

 Admiralty Islands. March 1, 1875. Lat. 2° 33' 0" S., long. 144° 4' 0" E. Depth 1070 

 fathoms. Blue mud. Bottom temperature 3 6° '4 Fahr.; surface temperature 84 o, Fahr. 



Genus Cnemidaster, n. gen. 



Disk small. Rays long, delicate, cylindrical, more or less rigid. Interbrachial arcs 

 rounded. 



Abactinal plates arranged in a single, regular, longitudinal line along the ray, covered 

 with thin skin and bearing no granules or spinelets. Abactinal covering of disk composed 

 of the primary apical plates, all large and convex, covered with thin skin and bearing no 

 granules or spinelets. 



Supero-margiual larger than the infero-marginal plates ; both series covered with skin 

 and bearing no granules or spinelets (excepting a few of the infero-marginal plates in the 

 interbrachial arc, which may bear appendages similar to those on the actinal intermediate 

 plates). 



Actinal intermediate plates, two series present bearing small compressed sacculated 

 spinelets, appressed to the ray and forming longitudinal series along the ray. 



Adambulacral plates broader than -long, with a prominent angle into the furrow (all 

 equally prominent), and a transverse median keel. Armature consisting of a transverse 

 series of short spinelets, equidistantly spaced on the keel. 



Madreporiform body small, circular, exposed, situated external to the adjacent primary 

 basal plate. 



Anal aperture distinct, excentric in position. 



No pedicellarise. 



Ambulacral tube-feet with a fleshy terminal knob, and forming two simple regular rows. 



Remarks. — This genus is distinguished from Zoroaster and the other forms in this 

 family by the large skin-covered abactinal and marginal plates, devoid of spinelets or 

 granules of any form. The armature of the actinal intermediate and of the adambulacral 

 plates is also characteristic. The starfish described by Perrier i under the name of Zoroaster 

 sigsbeei is perhaps more nearly related than any other form known to me ; but the 

 description and the figure are both insufficient to enable me to say how close the relation- 

 ship may be. 



1 Bull. Mia. Comp. ZooL, Harvard, 1881, vol. ix. p. 5; Nouv. Archives Mus. Hist. Nat., 2e Serie, 1884, 

 t. vi. p. 195, pi. iii. fig. 2. 



