170 



THE DEPTHS OF THE SEA. 



[CHAP. iv. 



Although many of the echinoderms of the cold 

 area are common to the warm, the general facies 

 of the echinoderm fauna is different, and there are 

 a number of additional and very striking forms. 



Cidaris papillata, LESKE, is abundant at moderate 



Fio. 31. Allopora oculina, EHRENBERG. 



depths. On our second visit to the Holtenia ground 

 we dredged one small specimen of the handsome 

 urchin already described, Porocidaris purpurata. 

 A fine brilliantlv-coloured urchin of the Echinus 



