REPORT ON THE ASTEROIDEA. 281 
these knobs to form a small lineal series slightly oblique in relation to the aboral margin 
of the plate. 
The adambulacral plates are considerably broader than long. Their armature consists 
of a furrow series of three short, robust, slightly tapering but obtuscly tipped spinelets, 
radiating slightly apart; and the median spinelet is rather larger than its companions. 
On the actinal surface of the plate are two thick, short, robust, obtuse, stumpy spinelets ; 
and on the inner half of the ray frequently three, placed one behind the other. These are 
so large that they leave no room on the plate for anything but an occasional and irregularly 
placed granule. The margin of the plate is surrounded by a single series of large bead- 
like granules distinctly spaced. 
The actinal interradial areas extend as far as the fourth infero-marginal plate, and are 
covered with large plates or tabula, which resemble those on the abactinal area. The 
tabula are margined by bead-like granules, the separate plates being thus distinctly 
marked, and each plate bears from one to three short, robust, obtuse, papilliform granules or 
spinelets similar to those on the actinal surface of the adambulacral plates, all increasing 
slightly in size as they approach the mouth. 
The mouth-plates are large but not prominent. Their armature consists of a marginal 
series of four spines on each plate, which increase in size as they advance inward. There 
is thus a pair of large, cylindrical, obtusely tipped spines at each mouth-angle directed 
over and closing the actinostome. On the actinal surface of the plates are two large, 
robust, cylindrical spinelets, slightly larger than any of the other large obtuse spinelets 
on the actinal surface, and behind these are two granules forming with the two secondary 
or superficial spines just mentioned a lineal series. 
The tube-feet have large sucker disks; and the ambulacral furrows are narrow and 
closed over by the armature of the adambulacral plates. 
The anal aperture is subcentral and margined by one or two rings of granules, the 
inner series small, the outer larger and more irregular. 
The madreporiform body is conspicuous and situated about midway between the 
centre and the margin. Its surface is slightly convex and is marked with fine striation- 
furrows, which are much convoluted and meandriform. 
Colour in alcohol, a bleached ashy or yellowish white. 
Locality.—Simon’s Bay, Cape of Good Hope. Depth 5 to 18 fathoms. 
Remarks.—This species is readily distinguished from Calliaster childreni, Gray, the only 
other species of Calliaster at present known, by the obtuse and non-tapering rays, as well 
as by the less tumid supero-marginal plates, which distinctly increase in breadth as they 
approach the extremity, whilst in Calliaster children they slightly diminish. Calliaster 
baceatus is further characterised by the more numerous spines on the abactinal plates, 
which are more stumpy, as well as by the much coarser and peculiar bead-like granules 
that surround the tabula. In Calliaster childreni only the medio-radial series of tabula 
(zoOL. CHALL. EXP.—PART LI.— 1888.) 36 
