140 



4. S. sexforis. Orbicular, depressed, and as if trun- 

 cated ; with six oblong foramina; the vent near to the mouth. 

 Leske ap. Klein, Tab. 1. fig. 3, 4. ^ Recent. 



5. S. quinquefora. Orbicular, depressed, and sub- 

 reniform ; with five oblong foramina ; the vent near to the 

 mouth. Leske ap. Klein, Tab. xxi. fig. C. D. Recent. 



6. S. quadrifora. 



This appears to be only a variety of scutella emarginata, 

 in which only two of the three posterior foramina reach the 

 margin. It however differs in being somewhat subreniform. 



7. S. bifora. Obtusely trigonal and depressed ; with 

 two oblong foramina at the posterior part ; the vent distant 

 from the mouth. 



Echinod. bis perforatus. Leske ap. Klein, Tab xxi. fig. 

 A. B. Recent. 



8. S. bifissa. Cordato-orbicular, depressed ; with two 

 slits on the wider side, and an intermediate, projecting lobe, 

 with an undulating margin. 



Echinus auritus. Leske ap. Klein, p. 202. 



9. S. lenticularis. Orbicular, rather convex ; with five 

 short ambulacra with open apices ; the vent marginal. 

 Fossil. Grignon. 



10. S. orbicularis. Circular, and depressed towards the 

 margin ; the back rather convex in the centre ; ovato-acute 

 ambulacra ; the vent between the mouth and the margin. 

 Leske ap. Klein, Tab. xlv. fig. 6, 7. Fossil. 



11. S. fibularis. Small, orbicular, depressed, and rather 

 thick, the margin rounded ; the vent between the mouth and 

 the margin. Lang. lap. fig. Tab. xxxv. fig. ult. Fossil. 



12. S. placenta. 



This is the name applied by Lamarck to the echinus 

 which has been assumed above as the type of the genus 

 arachnius. 



13. S. par ma. Orbicular; the back rather convex; 

 with five subovate ambulacra, disjoined, at the apices ; and 



