ECHINOIDEA 273 



is elsewhere distributed from off Bodo on the Norwegian coast to 



Fig. 



152. — harva oi Cidaris cidaris ; from the dorsal side. x 62. 

 (After Prouho, Rech. s.L Dorocidaris papillata.) 



the Azores, the Cape Verdes, and the 

 Mediterranean. Also known from off St. 

 Paul's Rock ; the numerous records of its 

 occurrence in the West Indies and in the 

 Indo-Pacific are due to confusion with 

 other species. Bathymetrical distribution 

 ca. 50-1800 m. 



2. Poriocidaris Mrtsn. 



Primary tubercles on upper side of test 

 distinctly crenulate ; ambulacral pores not 

 conjugate. Primary spines with a few 

 more or less thorny ridges, the surface 

 otherwise very finely striated, but without 

 hairs. Oral primaries strongly serrate. 

 Collar of primary spines very long, ca. 5-7 

 mm., often swollen. Only one sort of 

 pedicellarise, a large, flat, bivalve form 

 (Fig. 153). 



This genus has hitherto generally been 



designated as Porocidaris, but erroneously, 



the true Porocidaris Desor being a fossil 



(Eocene) form, characterised by having a 



circle of pore - like depressions in the -^^^^"- J,^*^: ^^^^^Y® .P®*^!" 

 ^ . ^ cellaria of Poriocidaris 



areoles, and conjugate pores ; none of purpurata x 33 



