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 swperomarginal for m/eromarginal, and it is so 

 printed (p. 138, 1. 22), confusing the sentence. 



Loc. — Between Greraldton and Cape Naturahste, Western 

 AustraHa. 



Genus Calliaster, Gray. 



Calliaster spinosus,! sp. nov. 



(Plate xi., fig. 1-2.) 



R = 140 mm. ; r=45 mm. ; R=3 r. Br=4() mm. R = 

 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 

 papulae 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. (S'pmo5MS= provided with spines ; in reference to the spiny actinal 

 surface. 



