REPORT OF THE ECHINOIDEA—MORTENSEN eA 
‘| but I have succeeded in restoring the specimen to some degree, so that 
we can at least measure its length. 
In my /ngolf Echinoidea, loc. cit., I concluded that the Heméaster 
gibbosus of A. Agassiz cannot be maintained as a distinct species be- 
side the Atlantic 17. expergitus, but in view of their wide geographical 
separation I thought it advisable to keep the form from the Malay 
region as a separate variety, var. gidbosus. Clark did not agree there- 
with, but regarded the latter as simply identical with expergitus. I 
cannot agree with him inthis. So long as we know one form only from 
the Atlantic, the other only from the Malay region and Japan I do not 
think it justifiable to regard them as identical. If they were actually 
identical, we would be sure to find some specimens also in other regions, 
e. g., the Indian Ocean or in the southern Pacific, indicating its dis- 
tribution to be continuous. But so far no specimens have been found 
in any connecting locality. I rather expect that, when once an ex- 
tensive series of both forms becomes available, characters will be 
found by which we shall be able actually to distinguish them. 
Genus HYPSELASTER H. L. Clark 
HYPSELASTER AFFINIS, new species 
Localities —Station 5469, Atalayan Island (lat. 13°37’ N., long. 
123°28’ E.); 915 meters; June 18, 1909. One very fragmentary 
specimen. 
Station 5582, Darvel Bay, Borneo (lat. 4°20’ N., long. 118°59’ E.) ; 
1,629 meters; September 26, 1909. Two broken specimens. 
Station 5637, vicinity of Bouro (lat. 3°53’ S., long. 126°48’ E.) ; 
1,281 meters; December 10, 1909. Fragments of two dead tests. 
Type.—vU.S.N.M. No. E.7152, from station 5582. 
Description.—The type, the better of the two specimens from station 
5582, is 48 mm. long, about 40 mm. broad, and 32 mm. high; the second 
specimen from the same station is 48 mm. long, 38 mm. broad, and 31 
mm. high. The other specimens are too fragmentary to permit 
measuring them. The greatest height of the test is just behind the 
peripetalous fasciole, from where it slopes gradually backward; the 
posterior end of the test is subvertical, slightly inward-sloping, and 
distinctly concave. The anterior end of the test is 16-17 mm. high. 
rounded ; it is thus only about half as high as the posterior end. 
The petals are rather much sunken. The posterior petals are some- 
what less than half the length of the anterior ones, which latter are 
straight, only their anterior border lightly convex. The plates of the 
anterolateral ambulacra outside the petals with only one or two 
tubercles, or naked. The frontal ambulacrum less sunken and also 
narrower than the petals; at the peripetalous fasciole it rises almost 
to the level of the test, and there is only a faint depression in the frontal 
