1914] Dickerson: Fauna of the Martinez Eocene of California 121 



Dimensions. Diameter of calice, 12 mm. ; height, 9 mm. 

 Occurrence. Martinez of San Pedro Point, San Mateo County, 

 California. 



ECHINOIDEA 



CIDAKIS, sp., a 



Plate 6, figures 4a, 4& 



Test unknown. Spines long, very slender, circular in cross-section. 

 Certain incomplete specimens are 15 mm. long and only 1 mm. in 

 diameter with only a slight taper. Surface of spine marked by micro- 

 scopic, longitudinal, lines or ribs. The distal end is marked by a 

 small ball which is decorated by about fourteen strong rounded ribs. 

 This ball terminates in a rounded tip. The base is marked by a well- 

 developed collar and a rounded socket in its end. The base does not 

 appear to be ornamented. 



The surface of the rock is covered with pieces of spines which have 

 been weathered out. The description is based upon several fragments 

 of spines. 



Occurrence. University of California Localities 245 and 1556, 

 Martinez Group. 



CIDARIS(?), sp., c 

 Plate 6, figures 6a, 6b 



A cast of a hemispherical test with the mouth and apical system, 

 central was found in beds of Martinez north of Mount Diablo. 

 Dimensions. Height, 4 mm. ; diameter, 6 mm. 

 Occurrence. University of California Locality 1592, two and one- 

 half miles east of Clayton. 



SCHIZASTER LECONTEI Merriam 



Plate 6, figure 7 

 Schizaster lecontei. Merriam, J. C., Proceedings, California Academy of 



Sciences, Geology, vol. 1, pp. 164-165, 1899. 

 California Academy of Sciences, vol. 1. 



1 i Small forms averaging a little less than 20 mm. in length. The largest 

 specimen measured is about 23 mm. long. Test distinctly notched anteriorly by 

 the groove of the anterior ambulacrum truncated posteriorly; upper surface 

 much elevated, with a sharp ridge running from the apical system to the posterior 

 end, summit situated far back. Apical system eccentric, posterior, anterior to 

 the summit. 



"Ambulacra broad, sunken; anterior petals reaching a little more than half 

 way to the margin; posterior laterals very short, less than half the length of 

 the anterior pair, sometimes almost circular in outline. Ambulacral pores 

 elongated, apparently yoked. (?) Mouth opening well forward, broad two-lipped. 

 Anus high up on the truncated posterior end. 



