E C II I N I D iE . 3 



four cells, was kindly presented mc by Mr. Allen S. Hanckel, who discovered it in St. 

 Andrew's Parish, near Charleston. A. petrosa is a West India coral. 



Plate. I. Fio. 4, Cells, natural size. 

 " 4a, Outline of fragment. 



Locality. St. Andrew's. ' Cabiiiet F. S. H. 



Class, ECniXODEMATA. Order, ECHINI. Family, ECHINID^. 

 Genus, MELLITA.— Klein. 



M E L L I T A Q U I N Q U E P E A . Variety, AMPLA. 

 Plate I. Figs. 6, 6a and (>b. 



Scutella quinquefora, Lamk., An. sans Vert., Vol. 3, p. 280. 



Scutella quinquefora, Ravenel, Cat. Recent and Fossil Echinida? So. Ca., 1848, p. 4, No. 7. 



Mellita ampla, Holmes, MS. 



Mellita ampla, Ravenel, Cat. Recent and Fossil Echinidse So. Ca., 1848, p. 4, No. 8. 



Scutella quinquefora, L. R. Gibbes, Tuomey's Geol. So. Ca., appendix, p. xxiii. 



Description. Disk sub-orbicular, truncated posteriorly ; margin thin, slightly notched 

 opposite anterior ambulacrum ; upper surface moderately convex ; lower surface flat, or 

 slightly convex ; lunules five, open, long and narrow ; posterior lunule wider and about 

 one-fifth longer than the ambulacral petals, sub-ovate, open ; posterior pair longer than the 

 anterior or lateral petals ; ambulacral furrows on lower surface deep, branched ; branches 



dendritic. 



This shell was, ten years ago, referred with some hesitation to a new species, and called 

 M. AMPLA, on account of its great size. We now feel quite assured it is only a large 

 variety of Mellita quinquefora, Rav. The conditions for so great development, which 

 existed during the Post-Pleiocene period, have passed away with that age ; and were pro- 

 bably owing to the gulf stream washing the shores of South-Carolina before the upheaval 

 of our low country. Individuals of the present period, now living in the waters of the 

 coast, seldom attain one-half the size of their fossil congeners. It is also worthy of 

 remark, that few small specimens, or young shells of this species, are found in a fossil state, 

 though large ones are abundant. 



