IvCHJNOIDHA. I. j,g 



Only one species: Pscudcch. alboc/i/c/its (Hiitton). 

 Distribution: New Zealand. Littoral form. 



Heliocidaris Desnil. (emend.) 

 (Synon\in: Evixliinits Verr.) 



Pores trigeminate; primary tubercle only on every second or third umljulacral plate. The 

 buccal membrane with numerous fine fenestrated plates hidden in the skin. No spines on the buccal 

 plates. The triphyllous pedicellaritc with peculiar, digitate processes from the ajjophysis (in all the 

 other genera the triph>llous pedicellaria; are constructed in the usual wa\). The spines short, strong, 

 greenish; the secondary spines club-shaped. The form of the test regular, Eclii)iiis-\\V<i. 



Species: //. chloroticus (Val.), raritubcrculatiis (Bell), aiistraU(r Woods (? — not examined). 



Distribution : New Zealand, Australia. Littoral forms. 

 Echinostrephus Ag. (emend.) 



Pores trigeminate, more rarely (luadrigeminate; primar\- tubercle on all the ambulacral plates. 

 The buccal membrane with numerous fenestrated plates, most of which carrv pedicellariEe. No spines on 

 the buccal plates. The form of the test very peculiar, flat and broad above, narrow below. The spines 

 rather thin, black; those of the upper side long, directed straight upward. 



Species: Ech. i/iolarc (Blv.), priitaoojttts Yosh. (? — not examined). 



Distribution : The Indo-Pacific Ocean. Littoral forms. 



Toxocidaris Ag. (emend.) 



Pores multigeminate; primary- tubercle on all the ambulacral plates. The luiccal membrane 

 with rather few plates most of which carry pedicellariie; no spines on the buccal plates. The form 

 of the test regular, i?r/«««j-like. The spines rather long and thick. 



Species: T. tuberculatHs (Lamk.), erythrogrannnus (\^al.), annigrr (Ag.). 



Distribution: Australia. Littoral forms. 

 Echinometra Rond. (emend.) 



Pores multigeminate; primar}- tubercle on all the ambulacral plates. The buccal membrane 

 with numerous fine fenestrated plates hidden in the skin, of which only a few carry pedicellarise. 

 Spines on the buccal plates. The form of the test more or less oblong. The spines rather long 

 and thick. 



Species: Ec/i. liicui/frr (L.l, vin'dis Ag., AlatJiaci (Blv.), ohloi/ga (Blv.), 7<aii Bruiiti Ag., viacro- 

 sfoiiia (Ltk.) (?). 



Distribution: Cosmopolitan in the warm zone. Littoral form.s. 



Heterocentrotus Brandt (emend.). 

 Pores multigeminate; primary tubercle on all the ambulacral plates. The buccal membrane 

 with numerous fenestrated plates, partly hidden in the skin. Spines both on the buccal plates and on 

 some of the plates outside of these. The test oblong. The primar\- spines exceedingly large aiul thick, 

 mostly edged; the secondary ones short, truncate. 



Species: //. in am ilia fits (Klein), trigonariiis (Lamk.). 

 Distribution: The Indo-Pacific Ocean. Littoral forms. 



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