106 " ENDEAVOUR " SCIENTIFIC RESULTS. 



relatively sUght, except as accident or attrition may decrease 

 the length. 



With reference to the generic name of this species, I think 

 Lambert and Thiery 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 obhged to reject his proposed genus Poriocidaris. In- 

 cluding purpuratus, Histocidaris is one of the most natural 

 genera yet recognised in the family. 



Locs. — Eastern Slope, Bass Strait, 80-200 fathoms. 



East of Fhnders Island, Bass Strait, 100-300 fathoms. 



Family CENTRECHINID^. 

 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. 



