CRETACEOUS ECHINODERMATA. 83 



Genus CARDIASTER Forbes. 



Cardiaster cinctus (Morton). 



Plate XXXVI, figures 2a-h. 



Spatangus sp. Morton, 1829, Acad. Nat. Sci. Philadelphia Jour., lstser., vol. 6, p. 122. 

 Ananchytes sp. Morton, 1830, Am. Jour. Sci., lstser., vol. 17, p. 2S7. 



Ananchytes cinctus Morton, 1S30, Acad. Nat. Sci. Philadelphia Jour., lstser., vol. 6, p. 200. 

 Ananchytes Jimbriatus Morton, 1830, Acad. Nat. Sci. Philadelphia Jour., lstser., vol. 6, p. 200. 

 Ananchytes cinctus Morton, 1830, Am. Jour. Sci., lstser., vol. 18, p. 246, PL III, fig. 7. 

 Ananchytes Jimbriatus Morton, 1830, Am. Jour. Sci., lstser., vol. 18, p. 245, PI. Ill, fig. 9. 

 Ananchytes cinctus Morton, 1834, Synopsis Organic Remains Cretaceous, p. 78, PI. Ill, fig. 19. 

 Ananchytes Jimbriatus Morton, 1834, Synopsis Organic Remains Cretaceous, pp. 77, 79, PL III, fig. 20. 

 Holaster cinctus Agassiz and Desor, 1840, Catalogue systematique, p. 1. 

 Holaster cinctus Agassiz and Desor, 1847, Catalogue raisonne, p. 133. 

 Holaster Jimbriatus Agassiz, 1S47, Catalogue raisonne, p. 141. 

 Holaster cinctus D'Orbigny, 1847, Prodrome, vol. 2, p. 269. 

 Holaster Jimbriatus D'Orbigny, 1847, Prodrome, vol. 2, p. 269. 

 Holaster cinctus Bronn, 1848, Index palseontologicus, vol. 1, p. 593. 

 Ananchytes Jimbriatus Bronn, 1848, Index palseontologicus, vol. 1, p. 70. 

 Cardiaster cinctus Bronn, 1853-1856, Lethsea geognostica, vol. 2, pt. 5, p. 205. 

 Cardiaster cinctus D'Orbigny, 1853-1860, Paleontologie francaise, vol. 6, p. 147; PL CMXCV, fig. 4. 

 Cardiaster Jimbriatus D'Orbigny, 1853-1860, Paleontologie francaise, vol. 6, p. 147; PL CMXCV, fig. 3. 

 Cardiaster cinctus (Cardiaster Jimbriatus) Desor, 1858, Synopsis desechinidesfossiles, p. 346. 

 Ananchytes cinctus Gabb, 1859, Cat. Invert. Fossils Cretaceous, p. 18. 

 Ananchytes Jimbriatus Gabb, 1859, Cat. Invert. Fossils Cretaceous, p. 18. 

 Holaster cinctus Credner, 1870, Deutsche geol. Gesell. Zeitschr. , vol. 22, p. 218. 

 Holaster cinctus Clark, 1891, Johns Hopkins Univ. Circ, vol. 10, No. 87, p. 77. 

 Cardiaster cinctus Clark, 1893, Johns Hopkins Univ. Circ, vol. 12, No. 103, p. 52. ' 

 Cardiaster cinctus Clark, 1893, U. S. Geol. Survey Bull. 97, pp. 75, 76, PI. XXXVII, figs. la-h. 

 Cardiaster Jimbriatus Johnson, 1905, Acad. Nat. Sci. Philadelphia Proc, vol. 57, p. 7. 

 Cardiaster cinctus Johnson, 1905, Acad. Nat. Sci. Philadelphia Proc, vol. 57, p. 7. 



Cardiaster cinctus Weller, 1907, Cretaceous paleontology of New Jersey: Geol. Survey New Jersey, pp. 296-297, PL XVI, 

 figs. 1-8. 



Determinative characters. — Test large, cordate, distinctly grooved anteriorly; contracted 

 posteriorly; upper surface convex; lower surface flat. Ambulacra wide. Apical system much 

 elongated, consisting of four perforated genital and five ocular plates situated slightly forward 

 of the center. Peristome near the anterior margin. Periproct oval, situated on the truncated 

 posterior margin. 



Dimensions. — Length 30 to 60 millimeters; width 25 to 55 millimeters; height 20 to 30 

 millimeters. 



Description. — This species, which is among the earliest of the Echinoid forms recognized 

 from American Cretaceous strata, is distinctly cordiform, with a pronounced groove on the 

 anterior face that is occupied by the unpaired ambulacrum. Opposite thereto is a slight ridge 

 at the central suture of the unpaired posterior interambulacrum which is suddenly terminated 

 by the nearly vertically truncated surface of the posterior margin. The sides decline equally to 

 the ambitus, giving an oval outline to the vertical lateral section. The lower surface is nearly 

 flat, with the exception of the slight depressions directly at the mouth edges and the elevated 

 area extending from the center of the base to the posterior margin. 



The ambulacra are wide, apetaloid, and separated at the apex. The anterolateral pair are 

 bent backward in their upper part, beyond which they extend straight to the margin. The 

 postero-lateral pair are bent somewhat forward, after which they extend straight over the margin. 

 The single ambulacrum is situated in the deep anterior sulcus. The pores of the paired ambu- 

 lacra consist, in the upper portion of the columns, of oblique oval openings united by furrows 

 while lower down they become small and often indistinct. In the unpaired ambulacrum the 

 pores are extremely small. 



The surface of the interambulacral as well as of the ambulacral plates is covered with fine 

 granules, among which are irregularly scattered numerous small perforated tubercles. 



