PLEIOCENE FOSSILS. 7 



closely clustered ; plate-ridges of the hinder pair of ambulacra widely separated ; anal 

 facet not preserved, but probably it was narrower, more rounded and more perpendicular 

 in its descent than that of A. orthonotus. All that remains of the nether surface, that is a 

 small portion of the second inter-ambulacrum of the right side, seems to indicate by its 

 relative position a more depressed form than is characteristic of either of the other species 

 described in this book. 



This species has some general resemblance to the wood-cut of A. Virginianus, given by 

 Prof. Forbes, in the London Journal of Geology, Yol. I., p. 425. But on closer comparison 

 it will be seen that the two forms differ especially in the shapes of the inner star-belt-field, 

 the convexity of the fore-shell, and the greater comparative breadth of the Carolinian fossil. 



Plate LT., Fig. 2. Upper view. In this figure, by con oversight of the artist, the field of the inner 

 star-belt is broader anteriorly by about the width of the belt on each side, 

 than it is in nature. 

 " 2a. Profile. 



Locality. The Grove, Cooper River, S. C. (J. McC.) 



AMPHIDETUS GOTHIGUS.— Kavenel. 

 Plate II., Fig. 3. 



Amphidetus gothicus. — Ravenel, Cat. of Echinoderrns Rec. and Foss, of S. C, p. 4. et fig. 

 (1848.) Charleston. 



Amphidetus maximus, alius, circumferentian circular is ; medio longitudine latissimus ; jugis 

 descendentibus inter ambulacr or urn parium posteriorum valde appropinquatis ; poris ambulac- 

 ralibus amplis, plusve minusve elongatis, paucibus et valde remotis in paribus collocatis ; area 

 fasciolae internae male conservata, sed probabiliter angustiore, tuberctdis parvis clavata / fa- 

 sciolae subanalis lata ; poris apertis intra fasciolam, numerosis, appropinquatis et ad apicem 

 sexualem per ting entibus. 



Description. This large species may at once be distinguished from the other fossil 

 Amphideti of America, by its circular form and great height. Its greatest breadth, also, is 

 about midway its length, the animal being proportionately narrow in front. The descending 

 plate-ridges of the second pair of inter-ambulacra are nearer together than in the other 

 species. The ambulacral pores few, large, and somewhat slit-shaped in the forward half-row 



