MIOCENE ECHIXODEEMATA. 215 



Description. — Weaver says : 

 The outline of the test from above is elliptical. The anterior groove is deep. The apical system is small and 

 situated slightly anterior to the center. The central portion of the lateral interambulacral plates forms a series of 

 irregular ridges extending from the apical system to the margin. The posterior interambulacral area is elevated. The 

 three anterior ambulacra are nearly equal in size and larger than the posterior areas as far as known. The poriferous 

 zones of the ambulacra are narrow, but the pores are large. The specimen is a poorly preserved cast and further data 

 are lacking. This species has been referred to Linthia rather than to Schizaster on account of the more central position 

 of the apical system. 



Dimensions. — Length 19 millimeters ; width 14 milhmeters; height 7 millimeters. 

 Locality. — One mile west of Bear Valley, Contra Costa. County, Cal. 

 Geologic horizon. — Lowest member of the Monterej* shale, middle Miocene. 

 Collection. — University of California. 



Genus BRISSUS Leske. 



Brissus spatiosus (Ravenel). 



Pericosmus spatiosus Ravenel, 1848, Echinidse, recent and fossil, South Carolina, p. 4. 



Hemiaster (Pericosmos) spatiosus Ravenel, 1850, Am. Assoc. Adv. Sci. Proc, vol. 3, p. 1G0. 



Brissus spatiosus McCrady, 1855, Pliocene fossils, South Carolina, p. 8. PI. Ill, figs. 1, la-c. 



Brissus spatiosus Meek, 1864, Check list. Miocene, p. 2. 



Meoma ventrieosa A. Agassiz, 1872, Revision of the Echini, pt. 1, p. 143. 



Meoma spatiosa Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 707. 



Description. — This species, which was named by Ravenel, was subsequently figured and 

 described by McCrady. It is regarded b}- A. Agassiz as a synonym of Meoma ventrieosa. No 

 specimens have been found for the present study, and in the absence of material it is difficult to 

 determine the true relations of the species, although it may well belong to the genus Meoma. 



Locality. — The Grove, Cooper River, S. C. 



Geologic horizon. — Duplin marl, upper Miocene. 



Collection. — Unknown. 



Genus METALIA Gray. 



Met alia raveneliana (McCrady). 



Plagionotus ravenelianus McCrady, 1855, Pliocene fossils, South Carolina, pp. 10, 11, PI. Ill, figs. 3, 3a. 



Plagionotis ravenelianus Meek, 1S64, Check list, Miocene, p. 2. 



Plagionotus ravenelianus A. Agassiz, 1874, Revision of the Echini, pt. 4. p. 751. 



Plugiobrissus ravenelianus Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 707. 



Description. — No material has been secured and it is therefore impossible to satisfactorily 

 describe this species. The genus Plagionotus is now regarded as a synonjon of Metalia. 

 Locality. — The Grove, Cooper River, S. C. 

 Geologic horizon. — Duplin marl, upper Miocene. 

 Collection. — Unknown. 



Metalia holmesi (McCrady). 



Plarjionotus holmesii McCrady, 1855, Pliocene fossils, South Carolina, pp. 9, 10, PL III, figs. 2, 2a. 



Plagionotus holmesii Meek, 1864, Check list, Miocene, p. 2. 



Plagionotus holmesii A. Agassiz, 1874, Revision of the Echini, pt. 4, p. 751. 



Plagiobrissus holmesi Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 707. 



Description. — No material has been secured and it is therefore impossible to satisfactorily 

 describe this species. The genus Plagionotus is now regarded as a synonym of Metalia. 

 Locality. — Goose Creek, S. C. 

 Geologic Tiorizon. — Duplin marl, upper Miocene. 

 Collection. — Unknown. 



