ECUINOIDEA. I. i,c 



vSpecies: Ecli. rscnlfiitiis L., (iciitas I^aiiik., viclo Lamk., clcgans Diib. Kor., gracilis Ag., Alcx- 

 andri Dan. Kor., Incidus Doderl, affiiiis n. sp., atlaiilicns w. sp. 



Distribution: The Atlantic Ocean, the Alediteiranean, the Pacific Ocean. Littoral-archiben- 

 thal forms. 



Sterechinus Koehler (emend.). 



Pores trigeminate; priniar\- tubercle on everv or onl\- on every otlier ambulacral plate. 

 The buccal membrane most frequently with numerous fenestrated plates inside of the buccal plates, 

 outside of these it is almost or quite naked. Generally one or more (all) of the ocular plates reach to 

 the periproct. The secondarx- spines often fine, silk\'; the actinal jirimarN- spines curved at the point 

 (always?). The globiferous pedicellarise generally with the edges connected across the inside of the 

 blade. The tridentate pedicellarije broad, leaf-shaped; tlie edge not thickened, onl\- with a single 

 series of teeth. 



Species: Stcrccli. iiiargtiritacrus (Lamk.), horridiis (Ag.), Nntiiiaycri 0'\&.i?A\)^ niagcllanicHs (Phil.). 



Distribution : The southern and western coasts of South America, the Antartic Seas. Littoral- 

 archibenthal forms. 



Paracentrotus n. g. 



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

 with fenestrated plates both inside and outside of the buccal plates (outside, however, rather few). 

 None or i — 2 ocular plates reach to the ])eriproct. The spines long and rather thick; the actinal ones 

 not curved at the point. In the globiferous pedicellarite the edges are not connected b\' cross-beams 

 across the inside of the blade. The tridentate pedicellaria; long, narrow, witliout transverse series of 

 small teeth. 



Species: Paraccntr. lividus (Ivamk.), Gaii)iardi (Blainv.). 



Distribution: The Mediterranean and the adjoining Atlantic coasts. Brazil. — Littoral form.s. 



Fam. Toxopneustidae Troschel (emend.). 



The globiferous pedicellarite with end-tooth, but without lateral teeth; the edges of the blade 

 quite coalesced on the inside, so that the blade is tubular. Peculiar dumb-bell-shaped or somewhat 

 branched .spicules are generalh' found in the globiferous pedicellaria; and often also in the tube feet; 

 bihamate spicules are generally also found; in one form {Sfroiigylocenfrofiis pnlclicyriiiiiis] o\\\\ biha- 

 mate .spicules are known. Generally i — 2 ocular plates reach the periproct. 



Subfam. Schizechininae Pomel (emend). 



The spicules in the globiferous pedicellarice dumb-bell-shaped or small bows not pointed at the 

 ends. Generally deep slits in the test. The globiferous pedicellarife without neck; mostly w'ith glands 

 on the stalk. The stalk compact. 



Genera: Psamniecliinus^ Gyiiutec/iiiiiis^ Toxop>icnstcs^ Tripiiciistes^ Sphcerechinus^ Pseudoboletia^ 

 Pseudoccntrohis. 



