ANNOTATED LIST. 145 
Sharks Bay, West Australia, and even to New Britain (Bell). It is not a large urchin, the 
test measuring 30 to 50 mm. in diameter in adults. The primaries are either smooth or 
thorny and the smooth reddish or purplish collar is unspotted. 
Prionocidaris verticillata. 
Cidarites verticillata Lamarck. 1816. Anim. s. Vert., 3, p. 56. 
Phyllacanthus verticillata A. Agassiz. 1873. Rev. Ech., pl. if, fig. 3. 
Prionocidaris verticillata Déderlein. 1911. Abh. Senckenb. Naturf. Ges., 34, p. 243. 
The Challenger took a specimen of this cidarid near Wednesday Island in 8 fathoms, 
but neither the Alert nor Semon found it, nor were we so fortunate as to meet with it. It 
has a very wide range, from Mozambique to Samoa northward to the Riu Kiu Islands and 
south to Torres Strait, but it is apparently not common anywhere and good series for study 
are still desiderata. It does not reach a large size (disk-diameter up to 40 mm.), but nothing 
is known of the growth-stages or of the degree of diversity which individuals may show. 
Phyllacanthus imperialis. 
Cidarites imperialis Lamarck. 1816. Anim. s. Vert., 3, p. 54. 
Phyllacanthus imperialis Brandt. 1835. Prodrome, p. 268.—A. Agassiz. 1873. Rev. Ech., pl. if, figs. 2, 6. 7. 
This fine cidarid ranges from Zanzibar and the Red Sea to and throughout the East 
Indies, southward to the Loyalty Islands, and along the east coast of Australia to Port 
Jackson. There is more or less diversity in the length and thickness of the spines, but 
material is not yet sufficiently abundant anywhere to enable us to decide whether the 
varieties which have been proposed and named are really of genetic significance. 
At Mer this species was not often met with, but it was not rare in its own particular 
habitat, which proved to be below low-water mark at the outer margin of the reef, a region 
where collecting is most difficult. The discovery of this habitat came about thus: We 
were anxious to secure specimens of Heterocentrotus and sought the aid of one of the most 
intelligent natives. A sea-urchin of some sort was shown him and then it was explained 
we wanted some animals like that, only with very big, thick spines, and a sketch was 
drawn to make sure he understood. He responded readily that he knew where to find them, 
so he was given a bucket and sent off, with the promise of sixpence apiece for all he could 
bring home. When he returned the bucket was nearly filled with Phyllacanthus imperialis, 
which he had secured off the northwestern reef by diving! He was quite disappointed 
that these were not the urchins desired. Other, but smaller, specimens were found on both 
the southeastern and southwestern reef-flats, under rocks near the reef-margin but above 
low-water mark. 
CENTRECHINID£E. 
It is unfortunate that the familiar name for this family, Diadematidz, must be aban- 
doned, but since there seems no doubt that Centrechinus must replace Diadema, the family 
name must also be altered. 
Centrechinus savignyi. 
Diadema savignyi Michelin. 1845. Rev. Mag. Zool., p. 15. 
(Plate 17, Figures 1 and 2.) 
This species is very much more common at Mer than the following, but it is by no 
means abundant. It is easily distinguished by the blue lines, not spots, on the dorsal side, 
the claret-colored oral region, and the entire absence of white. There is often a purplish- 
red tinge to the whole animal, and this may become very marked in preserved specimens. 
I suspect that Saville Kent’s (1893) figure (chr. pl. x1, fig. 12) of Diadema setosa, said to be 
natural color, is based on savignyi, but as it shows white and blue spots, it is more repre- 
sentative of setosus. His account of setosa shows that he did not think of there being two 
