ECHIXOIDEA. I. 139 



Onl\- one species: Pscitdccli. albocii/chis (Hutton). 

 Distribution: New Zealand. Littoral form. 



Heliocidaris Dcsnil. (eniend.) 

 (Synon>-ni: Evrcliiints Verr.) 

 Pores trigeminate; iDrimary tubercle only on every second or third ambulacral plate. The 

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

 piates. The triphyllous pedicellariæ with peculiar, digitate processes from the apophysis (in all the 

 other genera the triphyllous pedicellariæ are constructed in the usual way). The spines short, strong, 

 greenish; the secondary spines club-shaped. The form of the test regular, Echinus-X\V.^. 



Species: H. chloroticus (Val.), rarHuberculatiis (Bell), anstmliæ Woods (? — not examined). 

 Distribution: New Zealand, Australia. Littoral forms. 



Echinostrephus Ag. (eraend.) 



Pores trigeminate, more rarely quadrigeminate; primary tubercle on all the ambulacral piates. 

 The buccal membrane with numerous fenestrated plate.s, most of which carr\- pedicellariæ. No spines ou 

 the buccal piates. 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. iiwlarc (Blv.), pcntagonns Yosh. (? — not examined). 



Distribution: The ludo-Pacific Ocean. Littoral form.s. 



Toxocidaris Ag. (emend.) 



Pores multigeminate; primar\- tubercle on all the ambulacral piates. The buccal membrane 

 with rather few piates most of which carry pedicellariæ: no spines on the buccal piates. The form 

 of the test regular, Echimis-VC^ft. The spines rather long and thick. 



Species: T. hibcrculatus (Lamk.), crythrogrammiis (Val.), arniigcr (Ag.). 



Distribution: Australia. Littoral forms. 

 Echinometra Rond. (emend.) 



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

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

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

 and thick. 



Species: EcJi. htciD/fcr (L.), virid/s Ag., Mathnci (Blv.), obhviga (Blv.), va)i Brmiti Ag., »lacro- 

 sfoma (Ltk.) (?). 



Distribution: Cosmopolitan in the warm zone. Littoral forms. 



Heterocentrotus Brandt (emend.). 

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

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

 some of the piates outside of these. The test oblong. The primar\ spines exceedingly large and thick, 

 mostly edged; the secondar}- ones short, truncate. 



Species: //. i/iauiillafiis (Klein), fn'go>iarii(s (Lamk.). 

 Distribution: The Indo-Pacific Ocean. Littoral forms. 



1 8* 



