MEXICAN FOSSIL ECHINI — JACKSON 229 



Order CIDAROIDA Duncan 



Family CIDARIDAE Gray 



Genus CIDARIS Leske 



CIDARIS LOVENI Cotteau 



Cidaris loveni Cotteau, Kongl. Svenska Vet.-Akad. Handl., vol. 13, no. 6, p. 10, 

 pi. 1, figs. 11-14, 1875. — Jackson, Carnegie Inst. Washington Publ. 306, 

 p. 19, pi. 1, figs. 8-10, 1922. 



A fragment consisting of an interambulacral area and a lialf-ambu- 

 lacral area appears referable to this species, although it is considerably 

 larger than the type, which is from the Eocene of St. Bartholomew, 

 West Indies. The Mexican specimen measures 29 mm in height, width 

 of the interambulacrum at the midzone 22 mm, width of the half- 

 ambulacrum at the same zone 3 mm. Tliis, of course, indicates 6 mm 

 as the width of the ambulacral area. This species is recorded quali- 

 fiedly as Cidaris cf . loveni by Kew and also by Israelsky as from Tuxpan, 

 based apparently on the same specimen here considered. 



Miocene, Tuxpan formation, Tuxpan, Veracruz, Mexico; Dumble 

 and Cummins, collectors, 1908, California Academy of Sciences, 

 locahty X 14, one specimen. 



CIDARIS THOUARSn Agassiz and Desor 



Cidaris thouarsii Agassiz and Desor, Catalogue Raisonn^, Ann. Sci. Nat., ser. 

 3, vol. 6, p. 326, 1846. 



A specimen somewhat crushed but otherwise fairly well preserved 

 is referred to this species. It measures 17 mm in height, width of an 

 ambulacrum at the midzone about 3 mm, width of an interambula- 

 crum at the same zone 14 mm. Cidaris thouarsii occurs in the 

 Recent fauna of the Pacific off the west coast of Mexico. It is of 

 interest that it is found also in the fossil state in Mexico. C. tribu- 

 loides, which is abundant in the Recent West Indian fauna, has been 

 found fossil in Cuba. 



Miocene, Tuxpan formation, Tuxpan, Veracruz, Mexico; Dumble 

 and Cummins, collectors, 1908, Cahfornia Academy of Sciences, 

 locality X 14, one specimen. 



Order CENTRECHINOIDA Jackson 



Suborder Stirodonta Jackson 



Family STOMOPNEUSTIDAE Mortensen 



Genus STOMOPNEUSTES Agassiz 



STOMOPNEUSTES PRISTINUS, new species 



Plate 12, Figure 1 



Test low, dome-shaped, ambitus below the midzone, slightly pen- 

 tagonal in horizontal outline, the ambulacral areas coinciding with 



