3 o 4 CRETACEOUS PALEONTOLOGY. 



Remarks. This species is represented by numerous flattened 

 casts, none of which show clearly the original form of the test, 

 although it is apparently somewhat flatter than the other New 

 Jersey Cretaceous members of the genus. The species is related 

 to both Hemiaster parastatus and H. vttelleri. From the former 

 it is separated by its shallower and narrower ambulacral petals 

 and less elevated form ; from, the latter by its longer and narrower 

 postero-lateral ambulacral petals and flatter form. 



Formation and locality. Woodbury clay, Lorillard (102). 



Geographic distribution. New Jersey. 



Genus LINTHIA Merian. 



Linthia tumidula Clark. 

 Plate XVIII., Figs. 1-9. 



1891. Linthia tumidula Clark, Johns Hopkins Univ. Circ., vol. 



10, No. 87, p. 77. 

 1893. Linthia tumidkda Clark, Johns Hopkins Univ. Circ., vol. 



12, No. 103, p. 52. 

 1893. Linthia tumidula Clark, Bull. U. S. G. $., No. 97, p. 91, 



pi. 50, figs, i a-i. 



Description. Test ovate, distinctly cordiform, the ventral sur- 

 face flat except for the peristomal depression, the dorsal surface 

 elevated, with flattened, sloping sides, a moderately impressed 

 anterior sulcus which produces the emargination of the anterior 

 margin, and a distinct anterior median keel. Ambulacral areas 

 straight, narrow, impressed to a moderate depth for a long dis- 

 tance upon the dorsal surface, the anterior-lateral pair one and 

 one-half times as long as the postero-lateral pair; the poriferous 

 zones broad and straight, the pores large and oval, those of each 

 pair connected by a shallow furrow. Interambulacral areas 

 broad, composed of large plates. Surface of the test covered with 

 minute, perforated tubercles that are much larger on the ventral 

 than on the dorsal surface, between the tubercles the surface is 

 covered with microscopic granulations ; both the peripetalous and 

 the lateral fascioles clearly defined. Apical disk small, nearly 



