JAPAISIESE ASTEEOIDEA. 31 



" Station 44. May 2, 1873. Lat. 37° 25' 0" N., long. 71° 40' 0" W. 

 Depth 1700 fathoms. Bhie mud. Bottom temperatm-e 37°.2 Fahr. ; siu-face 

 temperatm-ô 49°. 5 Falii'." 



Pararchaster armahis, which is looked upon by Veeeill as another 

 synonym of the present species, is described by Sladen as follows ['89, p. 

 19] : 



" Parat'chaster armatus, n. sp. (PI. I, figs. 5 and 6 ; PI. IV, figs. 5 

 and 6). 



" Rays five. K, = 37 mm. ; r = 6 mm. II > 6 r. Breadth of a ray between 

 the second and third supero-marginal plates, 4 mm. 



" Raj's elongate, narrow and attenuate outwardly, tapering from the base 

 to the extremity ; subdepressed, with low vertical walls, and consequently 

 nearly rectangular in section. Disk small. Abactinal surface flat and level. 

 Actinal sm-face very slightly prominent at the mouth-angles. Interbracliial 

 arcs wide and well-rounded. 



" The abactinal surface of the disk and rays is covered with a plating 

 of small, thin, subcircular spicules, overlaid with a delicate membranous 

 tissue. The spicules bear centrally one, or sometimes two, and rarely thi'ee, 

 very small papilliform thornlets, of uniform character tlnoughout, excepting 

 a few on the disk which are slightly larger, but still quite inconspicuous 

 and unnoticeable without close examination. Occasionally in some examples 

 two or tlu'ee x^edicellarian apparatus may be present, — these are of the double 

 comb or spiracle-like form ; their structm'e is very simple, and the spinelets 

 composing them are comparatively large, in fact, slightly larger than the 

 small thornlets usually borne on the spicules. 



" The supero-marginal plates, twenty-three to twentj-five in number 

 from the median inteiTadial line to the extremity, are elongate and low. 

 The length is about three times greater than the height, and the u^Dper 

 margin of the plate, though actually confined to the lateral wall of the ray, 

 is very shghtly bevelled upon the abactinal surface. Each plate bears 

 centrally on this margin a rather prominent tubercle, upon which is ai-ticu- 

 lated an elongate, tapering, sharply pointed spine, the third or fom-th from 

 the inteiTadial line measm'ing about 4.5-5 mm. in length. There are 



