232 PROCEEDINGS OF THE NATIONAL MUSEUM vol.84 



CLYPEASTER TOPILANUS, new species 



Plate 13, Figures 2, 3 



Clypeaster sp. a Kew, Proc. California Acad. Sci., ser. 4, vol. 7, no. 5, table facing 

 p. 128 (for localities listed), pp. 130, 131, pi. 23, fig. 2; pi. 24, fig. 2, 1917. 



Clypeaster sp. Israblsky, Proc. California Acad. Sci., ser. 4, vol. 13, no. 8, p. 140, 

 1924. 



Test moderately high, pentagonal, elongate anteriorly, truncate 

 posteriorly, with thick rounded margin, dorsally elevated into a low 

 dome, ventrally reentrant to the moderately sunken peristome. Apical 

 disk small, a little anterior to the center of the test. Periproct near 

 the posterior border of the test, 5 mm from it in the type, which 

 measures 96 mm in length. Ambulacral petals open at the tips, 

 poriferous areas narrow, moderately depressed, nonporiferous areas 

 only moderately elevated. 



There is a rather large number of specimens of this species. The 

 one selected as the type (U.S.N.M. no. 496278) measures 96 mm in 

 length, 80 mm in width, and 25 mm in height. With all the species 

 assigned to the genus Clypeaster, it is annoying to make still another, 

 but these specimens cannot be made to fit into any species known. 

 C. topilanus is nearest to C. planipetalus Cotteau, but it differs from 

 that in having shorter petals and being less open at the tips; also the 

 petals are straighter and the poriferous areas are narrower than they 

 are in planipetalus. C. topilanus is more massive and more strongly 

 pentagonal in outline than C. sanrajaelensis Israelsky, wliich is from 

 the Tampico region. 



The species that Kew figured as Clypeaster species a is evidently 

 the same as that described here as new. Kew did not give any de- 

 scription of his species a, but it is listed in his table of species from 

 the "San Fernando formation and associated beds." As noted on 

 page 125 (footnote) of Dickerson and Kew's paper, the name "San 

 Fernando" being preoccupied, the name "San Rafael" was proposed 

 as a substitute by Prof. E. T. Dumble. That name has now been 

 dropped, as it was a synonym of the Mes6n formation. Kew gave as 

 localities for his species a: Salitre Ranch, Tamaulipas; and hill at 

 extreme north of La Puerta Range, Hacienda Santa Fe, Topila, 

 Veracruz. 



In the material at hand there is a fine series from the Mes<5n for- 

 mation at abandoned Corona camp. Hacienda Santa Fe, Topila, 

 Veracruz, Mexico, 16 specimens. One specimen without locality is 

 marked locality X 83a, California Academy of Sciences. 



