: 920] 



Kew: Cretaceous and Cenozoic Echinoidea 



53 



Locality. — Holotype from Santa Cruz quadrangle, Santa Cruz 

 Comty, locality 109, on Bear Creek, four miles above its confluence 

 with the San Lorenzo River, California. 



CIDAEIS MARTINEZENSIS Kew, n. sp. 

 Plate 3, figures 2a, 2b, 2c 



Cidaris {?) sp. c. Dickerson, Univ. Calif. Publ., Bull. Dept. GeoL, vol. 8, 

 1914, p. 121, pi. 6. 



Figured specimen. — No. 11400 Univ. Calif. Coll. Invert. Pal. 



Test of small size. Measurements of specimen no. 11400 : greatest 

 diameter 11.8 mm., greatest height 5.2 mm. Upper surface somewhat 

 flattened, lower surface concave to the peristome. Peristome very 

 large. Ambulacra rather broad. Interambulacra bearing two rows 

 of large priraarj^ tubercles whose areolas closely approach each other ; 

 outer areas marked by a ring of granules. The casts of spines of this 

 species are long, measuring at least 10 mm. in length. 



Geologic horizon. — Martinez group. Lower Eocene. 



Locality. — Swett's ranch. Contra Costa County, California. 



CIDAEIS MEREIAMI Arnold 

 Plate 3, figure 3 



Cidaris merriami Arnold. Proe. U. S. Nat. Mus., vol. 34, 1908, p. 359, pi. 

 32, fig. 8. 



Cidaris merriami. Stefanini, Boll. Soo. geol. ital., vol. 30, 1911, p. 696. 

 Cidaris merriami. Clark and Twitchell, U. S. Geol. Surv. Mon., vol. 54, 



1915, pp. 114-115, pi. 55, fig. 4. 

 Cidaris sp. (d) Dickerson. Univ. Calif. Publ., Bull. Dept. Geol., vol. 8, 



1914, p. 121, pi. 6, figs. 6a-6b. 



Holotijpe.— No. 165438 U. S. Nat Mus. 



Inasmuch as no further characters were obtainable from the 

 specimen at hand, Arnold 's original description will be given : 



The test of this species is unknown, but the abundance and well-marked 

 characteristics of the fragments of the spines lias been deemed of enough 

 importance to justify a specific name. Seven specimens have been obtained at 

 the type locality, each showing the characters described above. 



Spines subeircular in cross section, as much as 4 millimeters in diameter and 

 probably over 40 millimeters in length, tapering very slightly; surface sculptured 

 by 13 or 14 prominent, narrow, nodose, ridge-like, longitudinal ribs separated 

 by narrow, deei)ly incised grooves; the nodes are well defined, especially in the 

 younger stages of growth, and are subellijjtical in cross section, their longer 

 axis being parallel with the axis of the spine. 



