ECHINOIDEA. I. 



135 



Species: EcJi. iscnlrntits L., acittus Lanik., )iiclo L,amk., clrgaiis Ditb. Kor., gracilis Ag., Alcx- 

 andri Dan. Kor., lucidiis Doderl., affinis n. ,sp., atlaiiticits n. .sji. 



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

 thal forms. 



Sterechinus Koehler (emend.). 



Pores trigeminate ; primary tnbercle on every or only on every other ambnlacral plate. 

 The bnccal niembrane most freqnently witli numerons fenestrated piates inside of the buccal piates, 

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

 the periproct. The secondary spines often fine, silky; the actinal primary spines curved at the point 

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

 blade. The tridentate pedicellariæ broad, leaf-shaped; the edge not thickened, only with a single 

 series of teeth. 



Species: Stcrccli. )iiargaritaccus (Lamk.), horridus (Ag.), Ncmnaycri [W^x'A^n), viagcUanicus (Phil). 



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

 archibenthal forms. 



Paracentrotus n. g. 



Pores multigeminate. Primary tnbercle on all the ambnlacral piates. The buccal niembrane 

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

 None or 1 — 2 ocular piates reach to the periproct. The spines long and rather thick; the actinal ones 

 not curved at the point. In the globiferous pedicellariæ the edges are not connected by cross-beams 

 across the inside of the blade. The tridentate pedicellariæ long, narrow, withotit transverse series of 

 small teetli. 



Species: Paracriitr. lividus (Lanik.), Gaiinardi (Blainv.). 



Distribution; The Mediterranean and the adjoining Atlantic coasts. Brazil. — Littoral forms. 



Fam. Toxopneustidæ Troschel (emend.). 



The globiferous pedicellariæ 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' foinid in the globiferous pedicellariæ and often also in the tube feet; 

 bihamate spicules are generally also found ; in one form {Strongylocentrotus pulclicrrijiius) o\\\\ biha- 

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



Subfam. Schizechininæ Pomel (emend). 



The spicules in the globiferous pedicellariæ duinb-bell-shaped or small bows not pointed at the 

 ends. Generally deep slits in the test. The globiferous pedicellariæ without neck; mostly with glands 

 on the stalk. The stalk compact. 



(xenera: Psaiiiiiiccliiiius^ GyiJn/ccJii/nt.s\ Toxopiiciistcs, Tripiicustfs^ Sphærcchimis^ Pscudoboletia, 

 Pseudoccntrotus. 



