1920] Kew: Cretaceous mid Cenozoic Echinoidea 



83 



nent and larger tubercles. From A. whitncyi Remond it differs in 

 lacking the bell-shaped appearance of the former, in the wider petals, 

 and the much thicker margin. It may be separated from A. cier- 

 ioensis (Kew) by its much larger tubercles and more prominent 

 ambulacral furrows. 



Geologic horizon. — Upper San Pablo group (Santa Margarita for- 

 mation). Upper Miocene. This species is found associated with Astro- 

 dapsis margaritanus Kew. 



Localities. — Type of Conrad from Estrella, Monterey County, Cali- 

 fornia. It also occurs at Pence Enrico Canyon, Monterey County, 

 Univ. Calif, loe. 2727 ; moiath of Swains Canyon, north of Bradley, 

 Monterey County (U. S. Geol. Surv. Coll.) ; two miles south of San 

 Lucas, Monterey County (U. S. Geol. Surv. Coll.) ; Slacks Canyon, 

 Monterey County (Stanford Univ. Coll.) ; Wildhorse Canyon, Mon- 

 terey County (U. S. Geol. Surv. Coll.) ; three miles above San Lucas 

 (Stanford Univ. Coll.) ; Scott Valley, Santa Craz County, California 

 (Stanford Univ. Coll.). 



ASTEODAPSIS ARNOLDI, subsp. ARNOLDI (Pack) 

 Plate 21, figures 3a, 3b, 3c 



Astrodap.sis aiitiselU, var. arnoldi Pack. Univ. Calif. Publ. Bull. Dept. 



Geol., vol. 5, 1909, pp. 279-281, pi. 21, figs. 1, 2. 

 Not Astrodapsis arnoldi (Twitchell). Clark and Twitehell, U. S. Geol. 



Surv. Men., vol. 54, 1915, pp. 199-200, pi. 95, fig. 1. 



Holotijpe.—Ho. 11030 Univ. Calif. Coll. Invert. Pal. 



Test modei'ately large. Measurements of holotype : anteroposterior 

 diameter 60 mm., transverse diameter 58.6 mm., greatest height 14.9 

 mm. Outline subcircular, with longitudinal axis slightly longer than 

 the transverse axis ; greatest transverse diameter somewhat posterior 

 to the center of the test. Margin rounded and slightly but broadly 

 notched in the ambulacral areas, the degree of notching being greater 

 in the two posterior areas. Upper surface considerably depressed in 

 the submarginal area, from which part it rises markedly to a rather 

 high apex, giving rise to a bell-shaped appearance, as in Astrodapsis 

 whitneyi Remond. Broad, deep depressions exist in the interambu- 

 lacral areas of the upper surface ; smaller ones are present along the 

 sides of the distal portions of the petals in the ambulacral areas. The 

 greatest elevation of the test is on the odd anterior petal immediately 

 in front of the very slightly posteriorly eccentric apical system. 



