150 THE ECHINODERMS OF TORRES STRAIT. 
Temnotrema sculpta. 
Temnotrema sculpta A. Agassiz. 1863. Proc. Acad. Nat. Sci. Phila., p. 358. 
Pleurechinus variegatus Mortensen. 1904. Siam. Ech., p. 84, pl. i, figs. 5, 6, 8, 19; pl. ii, fig. 6. 
(Plate 17, Figure 5.) 
It was a pleasant surprise to find this pretty little urchin in a cranny of a coral frag- 
ment on the southwest reef at Mer, October 21, 1913. It was particularly noted because 
it was the only little echinoid which we found during our stay at the island. I believe this 
is the first record for the species south of the equator. Comparison with specimens from 
Japan shows there is considerable variation in the amount of red at the base of the spines; 
in some individuals it is scarcely noticeable and is chiefly to be seen on the oral spines; 
in others it is evident on all the larger spines; and in some cases the whole basal half of the 
spine, especially near the mouth, is red. In all cases the banding of the spines is more or 
less distinct. In the Murray Island specimen, which is 8 mm. in diameter, the red is pres- 
ent only on the spines near the mouth and is not extensive there. 
STRONGYLOCENTROTID£E. 
Echinostrephus molare. 
Echinus molaris de Blainville. 1825. Dict. Sci. Nat., 37, p. 88. 
Echinostrephus molare A. Agassiz. 1872. Rev. Ech., pt. 1, p. 119.—H. L. Clark. 1912. Mem. Mus. Comp. 
Zoil., 34, pl. 105, figs. 10, 11. 
This remarkable sea-urchin ranges from southeastern Africa to Japan and to the 
Murray Islands. How much further eastward the distribution extends is not yet known, 
but in the Gilbert, Hawaiian, and Society Islands, molare is replaced by the allied species 
aciculatum. There seems to be no good figure extant of molare as it appears in life, but the 
photograph of aciculatum given in ‘‘Hawaiian and other Pacific Echini” (H. L. Clark, 
1912, pl. 105, fig. 9) answers perfectly well, for in the condition and from the point of 
view shown the two species are indistinguishable. At Mer, molare was fairly common on 
the southwestern reef, but its habits are such that it would easily be overlooked in ordinary 
reef-collecting, and even when detected it is very difficult to get the specimen, for of all 
sea-urchins, Echinostrephus is without doubt the rock-borer. No one who has seen the 
smooth, cylindrical holes, often 75 to 100 mm. or more in depth, in which the urchin fits 
like a piston in its cylinder, can doubt that the animal is itself the maker of its home. 
How the work is done I can not presume to say, but one may guess that the teeth and oral 
spines, aided perhaps by an acid secretion, are the tools used. Apparently when undis- 
turbed the urchin rests near the top of the hole, perhaps the abactinal surface is slightly 
extruded, but when the rock is struck or some similar stimulus given, the animal drops to the 
bottom of the cavity. We found it impossible to get them out of their holes by means of a 
hooked wire or any process of pulling; the animal permits itself to be pulled to pieces before 
it relaxes the spines enough to be drawn out. The only whole specimens we procured were 
those whose burrows were in rocks small enough to be lifted and carried ashore. Such rocks 
could be broken up and the sea-urchins thus have their homes removed from around them. 
ECHINOMETRID/E. 
Parasalenia gratiosa. 
A. Agassiz. 1863. Bull. Mus. Comp. Zodl., 1, p. 22.—1873. Rev. Ech., pl. iiid, figs. 1, 2. 
From Zanzibar to the Red Sea, north to Japan, south to New Caledonia, and east to 
the Paumotus extends the range of Parasalenia, but whether one species or two occur in 
this vast area is yet uncertain, though the indications are strong that there is only one. 
The genus is not yet known from Hawaii. 
One specimen was found at Green Island, Queensland, one at Erub, and three at Mer. 
These are all typical of gratiosa in every particular, and none of them showed in life, or 
