72 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES. 



Locality. — The yellow limestone of Timber Creek and Vincentown (type), N. J. 

 Geologic horizon. — Vincentown sand of Rancocas group, Upper Cretaceous. 

 Collections. — American Museum of Natural History, New York; Academy of Natural 

 Sciences of Philadelphia (1464) ; Johns Hopkins University. 



Family CASSIDULID.E. 



Genus PYGURUS Agassiz. 



?Pygurus geometrictjs (Morton). 



Clypeaster sp. Morton, 1S30, Acad. Nat. Sci. Philadelphia Jour., 1st ser., vol. 6, p. 202. 



Clypeaster geometrieus Morton, 1833, Am. Jour. Sci., 1st ser., vol. 24, p. 131, PI. X. 



Clypeaster geometrieus Morton, 1834, Synopsis Organic Remains Cretaceous, p. 7fi, PI. X, fig. 10. 



Pygurus geometrieus Agassiz and Desor, 1847, Catalogue raisonn£, p. 141. 



Clypeaster geometrieus Bronn, 1848, Index palaeontologicus, vol. 1, p. 312. 



Pygurus geometrieus D'Orbigny, 1S50, Prodrome, vol. 2, p. 270. 



Pygurus geometrieus D'Orbigny, 1853-60, Paleontologie francaise, vol. 6, p. 313, PI. CMXX, fig. 4. 



Pygurus geometrieus Desor, 1858, Synopsis des 6chinides fossiles, p. 313. 



Clypeaster geometrieus Gabb, 1859, Catalogue Invertebrate Fossils Cretaceous, p. 18. 



Pygurus (?) geometrieus Clark, 1891, Johns Hopkins Univ. Circ, vol. 10, No. 87, p. 77. 



Pygurus (?) geometrieus Clark, 1893, U. S. Geol. Survey Bull. 97, pp. 92, 93. 



Pygurus (?) geometrieus Johnson, 1905, Acad. Nat. Sci. Philadelphia Proc, vol. 57, p. 7. 



The type of this species was examined by the writer, but its state of preservation (that of a- 

 poor cast) is such that its generic relations can not be with certainty determined. Until further 

 material is obtained it seems best to defer its recognition. Although originally described by 

 Morton as a Clypeaster, it has been referred to the genus Pygurus by Agassiz, D'Orbigny, and 

 Desor. 



Locality. — Delaware and Chesapeake Canal, Delaware. 



Geologic horizon. — Matawan formation, Upper Cretaceous. 



Collection. — Academy of Natural Sciences of Philadelphia. 



Genus CATOPYGUS Agassiz. 



Catopygus oviformis Conrad. 



Plate XXIX, figures 2a-f . 



Catopygus oviformis Conrad, 1847, Acad. Nat. Sci. Philadelphia Jour., 2d ser., vol. 2, p. 39, PL I, fig. 9. 

 Nuelcolitcs oviformis (Catopygus) Conrad, 1868, Geology of New Jersey, App. A, p. 722. , 



Catopygus oviforviis Clark, 1891, Johns Hopkins Univ. Circ, vol. 10, No. 87, p. 76. 

 Catopygus oviformis Clark, 1893, Johns Hopkins Univ. Circ, vol. 12, No. 103, p. 52. 

 Catopygus oviformis Clark, 1893, U. S. Geol. Survey Bull. 97, pp. 64, 65, PI. XXVII, figs. 2a-f. 

 Catopygus oviformis Johnson, 1905, Acad. Nat. Sci. Philadelphia Proc, vol. 57, p. 7. 



Determinative characters. — Test ovate, broader posteriorly; upper surface nearly flat; apex 

 posterior to apical disk. Ambulacra narrow, subpetaloidal. Interambulacra wide; single inter- 

 ambulacrum elevated. Apical system excentric, nearer the anterior border. Peristome small, 

 excentric, nearer the anterior margin. Periproct oval, situated in a narrow sulcus, that termi- 

 nates above in a projecting arch. 



Dimensions. — Characteristic specimen: Length 25 millimeters; width 21.9 millimeters; 

 height 14 millimeters. 



Description. — The test of this very beautiful little form is ovate, with rounded, inflated 

 sides and elevated upper surface. The base is nearly flat, slightly concave in the vicinity of the 

 peristome, and lobed posteriorly. 



The ambulacra are narrowly lanceolate, subpetaloidal on the upper surface, the posterior 

 areas being much longer than the others. The plates in the petaloid portions are narrow but 

 beyond increase in breadth. 



The interambulacral plates are covered with minute tubercles, between which are numerous 

 microscopic granules. 



