MEXICAN FOSSIL ECHINI JACKSON 231 



side of Laguna del Carpintero from it ; California Academy of Sciences, 

 locality X 34. A specimen with petals broader and poriferous areas 

 wider than is usual in the species as a variant is from Tiixpan, Vera- 

 cruz, California Academy of Sciences, locaUty X 14. 

 Lambert ^ also records this species from Tuxpan. 



CLYPEASTER MARINANUS, new species 



Plate 12, Figure 2; Plate 13, Figure 1 



Test elongate, low, subpentagonal in outline, very thin on the bor- 

 ders, center only slightly elevated, ventrally nearly flat, slightly 

 reentrant around the mouth. Ambulacral petals relatively short, 

 slightly curved, open at the tips, nearly flush with the surface of the 

 test, poriferous areas not sunken. Apical disk sUghtly anterior to the 

 center. Periproct near the posterior end; in a specimen 72 mm long 

 the periproct is 6 mm from the border. Tubercles are small dorsally 

 and closely associated; ventrally they are larger and more deeply 

 sunken. 



There is a rather large series of specimens of this species from several 

 locahties. The specimen selected as the type, H 120 (U.S.N. M. no. 

 496276), from Chamal on the north side of Soto la Marina River, 

 measures 102 mm in length, 94 mm in width, and about 20 mm in 

 height. Another specimen, from Hacienda Santa Fe, Topila, measures 

 116 mm in length, 98 mm in width, and about 17 mm in height. 



Clypeaster marinanus approaches in character nearest to C. rogersi 

 Morton but differs from that in having the test flatter and being much 

 thinner at the margin and less deeply reentrant around the mouth. 

 Also the ambulacral petals are shorter, narrower, and less curved, and 

 the poriferous areas are narrower in rogersi. C. marinanus differs 

 from C. staubi Lambert, which also occurs east of Soto la Marina, in 

 that the test of marinanus is much less conically elevated and much 

 less pentagonal in outline than staubi. 



Oligocene, Mes6n formation, at the following localities: Chamal, Soto 

 la Marina River, Tamaulipas, Mexico, Corona collection, six specimens 

 including the holotype ; Mes6n, Hacienda Santa F6, Topila, Veracruz, 

 six specimens; Lot 214 Hacienda Chinampa, 10 km east of town of 

 Chinampa, Canton Tuxpan, Veracruz, just above the main Lepido' 

 eyclina gigas beds, top of Mes6n formation, three small immature 

 specimens; east of Ozuluama, one specimen; Mes6n formation, Aguila 

 Colony, about 4 km northwest of the cathedral, Tampico, Mexico, 

 one specimen; north of Arbol Grande, between 3,700 and 4,300 feet 

 north of Arbol Grande station, near Tampico, Mexico, several frag- 

 ments; cut on street railway between Dona Ceciha and Tampico, 

 Mexico, one fragment, California Academy of Sciences, locaUty X 118. 



' Op. cit., p. 272. 



