110 



8. Spines red at the base; ophiceplialous pedi- 

 cellariæ not elongate; distinct lozenge-shaped 



figures on the test Amblypneustes formosus Val. 



Spines dark green at the base; ophice- 

 plialous pedieellariæ partly very elongate. 

 No lozenge-shaped figures on the test Amblypneustes oiniiu (Lmk.j. 



y. Two ocular plates reaching the periproct ; pri- 

 mary spines very prominent, not clubshaped Goniopneiistes pentagoniis (A. Ag.). 



No ocular plates reaching the periproct; 

 primary spines not prominent, clubshaped. 

 (Holopneustes.) 10. 



10. Ambulacra distinctly wider than interambu- 



lacra Holopneustes porosissinius Agass. 



Ambulacra not distinctly wider than inter- 

 ambulacra 11. 



11. Test high, eggshaped, narrowed towards the 



mouth; spines and test dark red Holopneustes purpurascens Llk. 



Test rather low, sphæroidal ; the actinal 

 side somewhat llattened; spines and test 

 faint reddish Holopneustes in/latus Ltk. 



The genera united by Agassiz in „Rev. of Ecli." under the name Temno- 

 pleuridœ have been universally acknowledged as forming a natural group. Only 

 Lambert') has a different view of their relations; he places the „Salmacinœ'' under 

 the Phijmosominœ, and the „Temnechince"' and „Pleurechinœ" under the Echininœ; 

 the Phijmosominœ, Arbaciadinæ and Echininœ being again placed as subfamilies 

 of the family Echinomelridœ. This classification gains no support at all from the 

 researches on the regular Echinids, represented here and in the .,Ingolf"-Echi- 

 noidea, nor from those of any other recent author on that subject, and Lam- 

 bert does not give more detailed reasons for assuming this classification; it can 

 then be dropped, I think, without further discussion. Duncan has shown, through 

 his excellent researches on the structure of the test of the Temnopleuridœ'-) that 

 the genera form two separate groups, the one having true pits undermining the 

 test and the plates being united by knobs and sockets, the other having only 

 suturai depressions or a raised ornamentation on the plates, the plates not being 

 united by knobs and sockets. In his „Revision" these groups are made subfamilies 

 of the fam. Temnopleuiidœ, the one, Temnopleurinœ, including the genera Temno- 

 pleurus, Pleurechinns (regarded as a subgenus only of the former), Temnechinus 



') Etude sur quLl(|uc i;cliiiiides de llnfra Lias et du Lias. Hull. Soc. Sc. de l'Youne. 1899. 

 ') On some Points in the Morphology of the test of the Temnopleuridœ. On the genus Pleur- 

 echinus. (J. Linn. Soc. XVI. 1881. J 



