1920] Kew: Cretaceous and Cenozoic Echinoidm 97 



Related forms. — This species is most closely related to Astrodapsis 

 grandis Kew, from which it is distinguished by its greater size, rela- 

 tively more depressed test, and slightly less elevated petals. It differs 

 from A. calif ornicus Kew in having narrower petals, a smaller madre- 

 porie area, and much less depressed intcrambulacral areas, those of 

 A. coalingaensis Kew being practically fiat; the petals of the former 

 continue raised to the margin, whereas in the latter they become flush 

 with the surface when a little over half way to the edge of the 

 test. The nearly flat intcrambulacral areas distinguish it from all 

 species of the A. tumidiis group. It differs from A. whitneiji Remond 

 in its less distinctly bell-shaped appearance; in having very slight 

 intcrambulacral depressions and less elevated petals ; the intcrambu- 

 lacral plates are more numerous on the abactinal surface ; and tlie 

 tuberculation is not uniform, whereas the tubercles in A. whitneyi 

 are small and similar over the entire test, a very distinctive character. 



Geologic horizon. — Upper San Pablo gi'oup (Santa Margarita for- 

 mation), Upper Miocene. Associated with Astrodapsis grandis Kew. 



LocaZfc.— Ilolotype from Sec. 12, T. 18 S., R. 14 E., M. D. B. 

 and M., North Coalinga district, Fresno County, California, Univ. 

 Calif, loc. 3076. 



ASTEODAPSIS CUYAMANUS Kew, n. sp. 

 Plate 19, figures la, 1& 



Eolotijpe.—^o. 11045 Univ. Calif. Coll. Invert. Pal. 



Size large. Measurements of holotype : anteroposterior diameter 

 66 mm., transverse diameter 64.3 mm., greatest thickness 12.5 mm. 

 Test greatly depressed, with margin thin but rounded. Marginal out- 

 line subcircular to subovate, with notclies in the ambulacral areas and 

 a smaller one in the odd posterior intcrambulacral area ; those in the 

 posterior ambulacral areas gi'eater than the others. Abactinal portion 

 of the interambulacra flat or faintly and broadly depressed. Am- 

 bulacra nearly twice the width of the interambulacra at the edge of 

 the test. Aj^ical system central, and somewhat sunken below the 

 general level of the upper surface ; situated very slightly anterior to 

 the center of the test. Summit immediately in front of the apical 

 system and located on the odd anterior petal. Petals markedly broad ; 

 the interporiferous ai'ea being three times the width of each poriferous 

 area ; petals of the bivium slightly narrower than those of the trivium ; 



