^ ECHINODERMS FROM WEST AUSTRALIA. 241 
I cannot find a single reliable character by which to separate this specimen 
from F. elegans, yet the abactinal plates iire not so large or well defined 
as in that species. The coloration is now pale brownish, but in life it 
must have been very similar to that o£ F. elegans, if we may trust the 
label. On the whole it seems better to refer these two specimens from 
" 1st Island " to F. elegans than to iuclflde them under the name 
F. andamanensis. 
BUNASTER LITHODES. 
W. K. Fisher, 1917, Proc. Biol. Soc. Wash. xxx. p. 91. 
There are four little ophidiasterids in the collections, two from Pelsart 
Island and two from Wooded Island, which undoubtedly belong to the 
genus Bunaster. They are certainly not B. ritteri, for pedicellariaa are 
present and there are no " ball and socket " plates, and they are not 
B. uniserialis, as comparison with the holotype of that species shows. 
After very prolonged study it seems best to consider them as young 
B. litJiodes, in the holotype of which species R = 22 mm. In none of the 
Abrolhos specimens does R exceed 10 mm. The most noticeable resemblance 
between these specimens and B. Utkodes is seen in the finely shagreen-like 
covering (aside from the abactinal plates) of the upper half of the animal ; 
in B. uniserialis the space between the abactinal plates is occupied by a 
coarse granulation, as it is in B. ritteri also. In two points the Abrolhos 
specimens are unlike B. lithodes ; the subambulacral spines are very little 
longer than broad, and it is hard to see more than a single row of actino- 
lateral plates even at the base of the arm. These two points may be 
dependent, however, upon maturity, and the characters are certainly liable 
to growth-changes. In view, then, of the obvious immaturity of these little 
Bunasters, I think they may well be referred to B. lithodes. 
The two specimens from Pelsart Island have R = 8 or 9 mm. They are 
shell-pink, faintly variegated with whitish and decidedly lighter below than 
above. One of the Wooded Island specimens has R = 9 mm., and the rays 
are distinctly more slender than in the others. Its colour is also a very 
much darker pink. The fourth specimen has R = 10 mm.; the rays are 
stout and the pink colour has been entirely bleached. 
Pethicia obesa*, sp. nov. (PL 13. figs. 1, 2.) 
Diagnosis : Rays wide, rounded at tip. Abactinal skeleton concealed by 
the very thick skin with which it is covered. No tubercles, spin'elets, or even 
granules on distal marginal plates. 
Description of Iwlotype : Rays 5. R = 65 mm. ; r = 30 mm. ; R = 2"17r. 
Br = 32 mm. Br at middle of ray = 24 mm. ; at 5 mm. from tip, 15 mm. 
Disk large, only slightly elevated ; arms wide, slightly arched, very blunt 
* Obesiis = fat, in reference to the wide, blunt rays and the thick skin. 
