ANNOTATED LIST. 101 
Report, aided by a good map, they are Flinders Island (a little south of latitude 14° S.) 
and Clairmont Island (north of lat. 14° S.) and either Albany Island near Cape York or 
the Alert Rocks near the western end of Prince of Wales Channel. If one could feel sure 
of the identification of the specimens, this would be most interesting. For Metrodira seems 
to be most common in the Bay of Bengal and extends from Ceylon and the Andaman 
Islands, southeastward to the Aru Islands and Torres Strait. If the Alert also found it on 
Clairmont and Flinders Island, there would be reason to believe it is extending its range 
through Torres Strait and down the coast of Queensland. But, unfortunately, I can not 
feel sure that these Alert specimens were Metrodiras, for there lies before me indisputable 
evidence that Bell is not familiar with this sea-star. Among specimens received by the 
Museum of Comparative Zoélogy from the British Museum in exchange in 1907, and labeled 
by Bell himself, are two fine Metrodiras from Holothuria Bank, northwestern Australia, 
which are identified and labeled as Echinaster purpureus! In his report on the Echinoderms 
of northwestern Australia (1894, Proc. Zoél. Soc., p. 392), Bell lists both Metrodira subulata 
and Echinaster purpureus without comment; that there was no sharp distinction between 
the two in his own mind seems very evident. The larger of the two specimens from Holo- 
thuria Bank has R =70 mm. and would seem to be the largest Metrodira as yet reported. 
Nothing is recorded of the color in life or of the habits of this sea-star. I follow Fisher 
(1919) in placing the genus in a family by itself, as I do also in the case of the two following 
forms, but I can not avoid the fear that we are emphasizing differences too much, rather 
than relationships, in thus multiplying families. 
ACANTHASTERID£E. 
Acanthaster planci. 
Asterias planci Linné. 1758. Syst. Nat. ed. x, p. 823. 
Acanthaster echinites Déderlein. 1896. Jena Denksch., 8, p. 320, pl. xxi, figs. 2-7. 
Acanthaster planci Verrill. 1914. Shallow-water Starf. N. Pac. coast, p. 364. 
It was quite a surprise to find this extraordinary sea-star at Mer. Only 3 specimens 
were seen, the largest 400 mm. across. One had only 14 rays, but each of the others had 16. 
The color in life was bluish-gray with the spines reddish at tip; the change from gray to 
red is not abrupt but gradual, apparently due to increasing amounts of rusty-red pigment 
in the skin. In some specimens only the tips of the spines are red, but in others that color 
extends downward towards or even to the base; if it spread further in the dorsal skin, we 
should have red individuals, such as those Déderlein records from the Riu-Kiu Islands. 
The spines of the lower surface are dull reddish-purple and the feet are white or pale yellow- 
ish. The disk and the sides and upper surface of arms basally are covered by the dull 
reddish-purple or brownish papulz. The entire coloration harmonizes so well with the general 
coloring of the reef that, in spite of its large size and remarkable spines, this sea-star is very 
inconspicuous and I doubt not is often overlooked. Those found at Mer were on the surface 
of the reef and not under rocks or coral slabs. Study of the 31 specimens in the Museum 
of Comparative Zoédlogy from various localities extending from Zanzibar and the Arabian 
Gulf on the west to the Society and Hawaiian Islands on the east (including Warrior Reef, 
Torres Strait, as well as Mer) has not enabled me to recognize more than a single species 
of Acanthaster,' but I have not seen specimens from Mauritius. Déderlein, however (1896), 
had six Mauritius specimens, and after comparing with East Indian material, only recog- 
nized 1 species. De Loriol’s account and figures of the Mauritius form (1885, Mem. Soc. 
Phys. Hist. Nat. Genéve, 29, No. 4, p. 6, pl. xii) are very important; his colored figure, 
however, is probably based on a dry specimen. 
1] have never seen specimens from the western coast of America, where a second species (ellisii) occurs, nor 
would I seem to question the validity of A. brevispinus Fisher. 
