206 PROCEEDINGS OF THE ACADEMY OF [Feb., 



DESCRIPTION OF A NEW ECHINODERM. 

 BY HENRY A. PILSBRY. 



Several years ago the Academy received from Mr. Clarence 

 Bloomfield Moore specimens of a fossil sea-urchin, which had been 

 obtained from- material dredged from near the mouth of the Withla- 

 coochee River, Florida, in an area mapped as Pliocene. The speci- 

 mens represent an undescribed species, which may be called — • 



Eupatagus mooreanus n. sp. Plate VIH. 



The outline is broadly ovate, slightly emarginate in front, tapering 

 a little, and abruptly, vertically truncate behind. The upper surface 

 is moderately convex, highest at the posterior third of the length; 

 lower surface nearly flat, slightly concave at the sides and anteriorly 

 close to the peristome, 



The ambulacral centre is at the anterior six-tenths of the length. 

 Unpaired ambulacral area indistinct, without large pores. Paired 

 ambulacral areas petaloid, nearly straight-sided, closed at the distal 

 ends. Those of the posterior pair are a little longer than the anterior. 

 They form an acute angle with one another and right angles with 

 the areas of the anterior pair. The poriferous zones are depressed, 

 with equal, circular pores in pairs connected by furrows. The four 

 genital pores are equal, round, the anterior pair much closer than the 

 posterior pair. The peripetalous fasciole is distinct, not sinuous. 

 The tubercles in the interambulacral areas are very unequal. The 

 larger ones stand in about five waved concentric series and occupy 

 slight depressions. The posterior interambulacral area is convex 

 and not distinctly tuberculate, having a quite distinct median suture. 



The peristome is in form of a transverse oval, flattened posteriorly . 

 It is situated at the anterior third of the length. The periproct 

 opens at the summit of the flattened posterior area, is shortly oval^ 

 somewhat higher than wide, and a little angular at the ends. The 

 base is closely and strongly tuberculate, the tubercles becoming 

 much smaller at the periphery. There is a smooth raised segment 

 from the peristome to the posterior end. 



Length 61, transverse diameter 51, alt. 29 mm. 



This species is about the size of E. clevei Cotteau, from which it 



