300 CRETACEO.US PALEONTOLOGY. 



The dimensions of a complete example are: length, 37.5 mm. ; 

 width, 37.5 mm.; height, 28.12 mm. 



Remarks, This species is most closely related to H. ungula, 

 from which it may be separated by its deeper and broader anterior 

 sulcus, more posterior position of the apical disk, and its more 

 inflated sides. 



Formation an\d locality. Vincentown limesand, Vincentown 

 and Timber Creek (Clark). 



Geographic distribution. New Jersey, Alabama. 



Hemiaster stella (Morton). 

 Plate XVI., Figs. 1-4. 



1830. Spatangus stella Mort., Am. Jour. Sci., ist ser., vol. i8 r 



p. 245, pi. 3, fig. ii. 

 1830. Spatangus stella Mort., Jour. Acad. Nat. Sci. Phil., ist 



ser., vol. 6, p. 200. 

 1834. Spatangus stella Mort., Synop. Org. Rem. Cret. Gr. U. 



S., p. 78, pi. 3, % 18. 

 1864. Hemiaster stella Meek, Check List Inv. Foss. N. A., Cret, 



and Jur., p. 3. 

 1891. Hemiaster incrassatus Clark, Johns Hopkins Univ. Circ., 



vol. 10, No. 87, p. 77. 

 1893. Hemiaster stella Clark, Johns Hopkins Univ. Circ., vol. 



12, No. 103, p. 52. 

 1893. Hemiaster stella Clark, Bull. U. S. G. S., No. 97, p. 84, 



pi. 46, figs, i a-d. 

 1905. Hemiaster stella Johns., Proc. Acad. Nat. Sci. Phil., 1905, 



p. 7. 



Description. Test small, ovate, inflated, rounded in front and 

 truncated behind, the ventral surface nearly flat, the dorsal sur- 

 face convex, strongly elevated near the posterior margin, sloping 

 anteriorly and lacking a distinct anterior sulcus. Ambulacral 

 areas petaloid, with the petals straight and depressed, the antero- 

 lateral pair twice as long as the postero-lateral pair, and the 

 unpaired anterior one longer than those of the antero-lateral pair. 

 Interambulacral areas broad, composed of large plates. Surface 



