44 ‘* ENDEAVOUR’ SCIENTIFIC RESULTS. 
Genus PENTAGONASTER, Gray. 
PENTAGONASTER STIBARUS, H. L. Clark. 
Pentagonaster stibarus, H. L. Clark, Rec. West Austr. Mus., 
i., 1914, p. 136. 
No doubt this specimen was taken with the types ; it adds 
nothing to our knowledge of the species ; there are, however, 
no abactinal tubercles, but R only=33 mm. By an un- 
fortunate slip of the pen in the original account of this species, 
in discussing the relative size of the marginal plates in the 
genus, I wrote superomarginal for inferomarginal, and it is so 
printed (p. 138, 1. 22), confusing the sentence. 
Loc.—Between Geraldton and Cape Naturaliste, Western 
Australia. 
Genus CALLIASTER, Gray. 
CALLIASTER SPINOSUS,! sp. nov. 
(Plate xi., fig. 1-2.) 
R=]40' mm. ; 1T=45° mm.» Kir.) br—40 mn 
3.5 br. Br at middle of ray, 18 mm.; at tip, 5 mm. Disk 
large, somewhat elevated at centre and along radii; arms 
abruptly narrowed and tapering gradually to the blunt tip. 
Abactinal surface covered by moderately large stellate plates, 
the central portion of which is swollen into a flattened hemi- 
sphere ; each of these rounded centres is surrounded by a 
circle of coarse granules, which more or less conceal the 
papulz arising singly between the plates, and is crowned by 
a group of coarser granules, the central one of which is dis- 
tinctly the biggest ; occasionally, though not commonly, one 
of these crowning granules is replaced by a large 2-jawed 
pedicellaria fitting into a special depression in the surface of 
the plate ; each jaw of the pedicellaria is broadly spatulate, 
rounded at the tip and, when open, lies back in the depression, 
so as to seem flush with the surface of the plate. The 
“ crowning ”’ granules differ from the ‘‘ marginal” granules, 
not merely in being, as a rule, larger, but in that they are more 
or less spherical, while the marginal ones are very flat. 
Along the midradial line of each ray, there is a series of 
plates which extend from the terminal plate, which is large 
and somewhat swollen (4 mm. long, 3 mm. wide proximally 
1. Spinosus=provided with spines; in reference to the spiny actinal 
surface. 
