84 THE ECHINODERMS OF TORRES STRAIT. 
Ophidiaster cribrarius. 
Liitken. 1871. Vid. Med., p. 277. 
This small species (R =30-50 mm.) is known as yet only from New Caledonia and 
Tonga. Liitken says that 6 of 24 specimens had 6 rays, while Perrier says one of his 8 
had 7. The only specimen in the Museum of Comparative Zodlogy has 5 very unequal 
rays and is from an unknown locality. Although no true comet forms have yet been 
recorded, all the indications are that cribrarius is one of the very few species of Ophidiaster 
which reproduce by fission. 
Ophidiaster robillardi. 
De Loriol. 1885. Mem. Soc. Phys. Hist. Nat. Genéve, 29, No. 4, p. 24, pl. xv, figs. 1-5a. 
This is the smallest member of the genus and is known as yet only from Mauritius, 
where it seems to be common. There are 18 specimens in the Museum of Comparative 
Zoology, collected by Nicholas Pike, U. 8. Consul at Mauritius many years ago, to whom 
the Museum is indebted for many echinoderms, not to mention animals of other groups. 
The largest of these robillardi has R =29 mm. and is thus much bigger than de Loriol’s 
largest, which had R=17 mm. All of the specimens have 5 rays, except 4 which are per- 
fectly tetramerous. There seem to be always 2 madreporites and, as a rule, the rays are 
very unequal. There are two perfect ‘‘comets,” one with the 4 new rays just visible, the 
other with them about 3 mm. long. There is no doubt that asexual reproduction by autot- 
omy occurs regularly and normally in this little Ophidiaster as in Linckia guildingii. It 
is worthy of note that the largest specimen among the 18 is one of the most symmetrical, 
and the tetramerous individuals also have their 4 rays remarkably equal. A parasitic 
gastropod, kindly identified for me by Mr. W. F. Clapp as a species of Stylifer, seems to 
be a serious enemy to this sea-star, as 6 of the specimens were serving as hosts and in one 
of these the swollen ray is occupied by 3 of the shells, each 4 to 5 mm. long by 2 to 3 mm. 
in diameter. 
Ophidiaster lorioli. 
Fisher. 1906. Bull. U.S. Fish Comm. for 1903, p. 1077, pl. xxxi, figs. 4-4d; pl. xxxix, fig. 3. 
This little species was taken on the reefs along the southern coast of Molokai, Hawaiian 
Islands. Probably the specimens of Ophidiaster from Oahu, called pusillus by Ives, 1889, 
were the same form. The holotype has R =31 mm., but a specimen in the Museum of 
Comparative Zoélogy from Samoa has R=41 mm. This individual was taken in Pagopago 
harbor, Tutuila, in 1917, by Mr. John W. Mills. It differs from Fisher’s description and 
figures only in a few details due to its larger size and probably greater age. For example 
there are commonly 5 or 6 papule in the abactinal area and 8, rarely 4, actinally. No 
two of the rays are of the same length but all are notably cylindrical and blunt, markedly 
different from the rays of robillardi. The furrow spines are barely separated from one 
another by small, flat granules, 7.e., one granule between every two spines. This condition 
occurs also in robillardi when adult, and there is no constant difference between the two 
species in this particular. In both species, even in large specimens, the granule is often 
lacking. Fisher says the color in alcohol is “‘bleached yellowish.”” My Samoan specimen, 
dried from alcohol, is pale fawn-color, almost whitish, with very faint indications of reddish 
blotches on the upper surface. 
DACTYLOSASTER. 
Gray. 1840. Ann. Mag. Nat. Hist., 6, p. 283. 
Genotype: Asterias cylindrica Lamarck, 1816. Anim. s. Vert., 2, p. 567. Type here 
designated for the first time. 
I have hesitated not a little over recognizing this genus, but have finally decided to 
do so because there is a very obvious peculiarity in the body covering, which makes the 
