584 THE VOYAGE OF II. MS. CHALLENGER. 



Coscinasterias muricata, Verrill, 1871 (18G7), Trans. Conn. Acad. Arts and Sci., vol. L part 2, p. 249. 

 Asteracanthion aiistralis, Perrier, 1869, Ann. Sci. Nat., 5e Serie, t. xii. p. 220. 



Asterias Jehennesii (Valenciennes, M.S.), Perrier, 1875, Re>is. Stell. Mus., p. 47 (Archives de Zool. 

 expdr., t. iv. p. 311). 



Localities. — Off Port Jackson. Depth and conditions not recorded. 



Station 162. Off East Moncceur Island, Bass Strait. April 2, 1874. Lat. 39° 10' 30" 

 S., long. 146° 37' 0" E. Depth 38 fathoms. Sand and shells. Surface temperature 

 63° "2 Fahr. 



20. Asterias (Stolaste?*ias) volsellata, n. sp. (PI. CVII. figs. 1-4). 



Rays eleven. R = 128 mm.; ?- = 10 mm. R<13r. Breadth of a ray at the base, 

 7 mm ; breadth about midway between the disk and the extremity, 5 mm. 



Rays elongate and narrow, tapering gradually to the extremity, the outer part being 

 very delicate and attenuate. Abactinal surface of the rays slightly arched and faintly 

 carinate; lateral walls high and vertical. Disk small, depressed, and well defined, the 

 rays readily becoming detached. Interbrachial arcs acute. 



The skeletal plates of the rays, which are narrow and delicate, are disposed with great 

 regularity. They form a median radial series, a supero-marginal series which bounds the 

 abactinal area, and an infero-marginal series which is contingent on the adambulacral 

 plates. Between these five regular longitudinal series of plates are transverse bars of 

 similar plates at subequal distances apart which form large quadrangular meshes, covered 

 with a thin delicate membrane. The plates in the longitudinal series, which stand at the 

 place of junction with the transverse bars, may be more or less cruciform, and bear a single 

 elongate and very delicate needle-like spine, the longest near the base of the ray measuring 

 about 4 mm. ; the spinelets are about 4 mm. apart. The base of the spine is invested 

 with a short membranous sheath, which is surmounted by a thick, densely crowded wreath 

 of forcipiform pedicel larise, the spinelet appearing as if passing through a globular mass 

 of these bodies. On the outer part of the ray the abactinal plates become very small and 

 quite aborted in character, the transverse bars which stretch from side to side being fre- 

 quently the most conspicuous, and then closely resemble the transverse bars of plates 

 occurring in Brisinga ; the wide intervening spaces covered only with semitransparent 

 membrane enhance the striking similarity. At the base of the ray the membrane which 

 covers the meshes is punctured with numerous small paj:>ula3 congregated in groups, 

 several groups being present in each mesh. Several rather large, elongate, isolated forfici- 

 form pedicellarise are borne upon the membrane, amongst and between the groups of 

 papulae. There are also a number of very large forficiform pedicellariae, having the jaws 

 broad, curved and expanded at the tips, which are armed with several large, interlocking 

 denticles ; these comparatively gigantic pedicellariae are generally placed singly at or near 

 the base of the large spinelets, and the frequency of this position leads to the supjwsition 



