3 
106 ‘* ENDEAVOUR” SCIENTIFIC RESULTS. 
relatively slight, except as accident or attrition may decrease 
the length. 
With reference to the generic name of this species, I think 
Lambert and Thiéry are right in objecting to any recent 
species being assigned to the genus Porocidaris ; it is very 
unlikely that any now known really belong there ; certainly 
none show the distinctive generic feature. On the other hand 
I think it still worse to put these characteristic recent forms 
into Pomel’s ill-defined and heterogenous group Plegiocidaris, 
as my esteemed French colleagues do, and I believe the best 
plan is to follow Mortensen in creating a special genus Histo- 
cidaris. I differ from him, however, in considering purpuratus 
as much a member of Histocidaris as is elegans, and hence I 
am obliged to reject his proposed genus Poriocidaris. In- 
cluding purpuratus, Histocidaris is one of the most natural 
genera yet recognised in the family. 
Locs.—Kastern Slope, Bass Strait, 80-200 fathoms. 
Kast of Flinders Island, Bass Strait, 100-300 fathoms. 
Family CENTRECHINID 2. 
Genus AsTRoPYGA, Gray. 
ASTROPYGA RADIATA (Leske). 
Cidaris radiata, Leske, Add. ad Klein, 1778, p. 52. 
Astropyga radiata, Gray, Ann. Phil., xxvi., 1825, p. 426. 
The finding of this conspicuous Sea-urchin so far to the south 
of its previously known range is one of the “‘ Endeavour’s ” 
many interesting discoveries. The “ Siboga ”’ took specimens 
near Ceram, north-west from New Guinea, but the genus has 
not hitherto been found in Torres Strait or anywhere on the 
Australian coast. The present specimens are 110 and 145 
mm. in diameter; the larger is dull dark red, the primaries, 
especially the actinal ones, with a greenish cast ; the smaller 
is reddish-white with actinostome, genito-ocular ring and outer 
half (or more proximally) of each abactinal interambulacral 
plate, rose-red ; the abactinal blue spots show up plainly on 
the smaller specimen, but are much less distinct on the larger 
and darker one. The actinal primaries of the smaller speci- 
men are prettily, transversely banded. ‘Two specimens. 
Loc.—Twenty-five miles south-east of Double Island Point, 
Queensland, 33 fathoms. 
