82 MESOZOIC AND CENOZOIC ECHINODEKMATA OF THE UNITED STATES. 



Dimensions. — Length 43.75 millimeters; width 37.5 millimeters; height 31.25 millimeters. 



Description. — The specimens of this species collected by the writer are remarkably well pre- 

 served and admit of the determination of all the essential features. The test is in lateral outline 

 subovate, though somewhat cordate in form when viewed from above or below. A marked pro- 

 tuberance is present on the posterior margin that appears as a slight ridge on the lower surface 

 between the peristome and periproct. The upper surface is convex. The sides are full and 

 rounded at the ambitus. The base is nearly flat, with the exception of the slight ridge and 

 depressed peristome. 



The ambulacra are wide and straight, attaining their greatest width just above the ambitus. 

 The pores are oval, and those of each pair are placed toward the ambitus at an angle to one 

 another. The surface of both the ambulacral and interambulacral plates is covered by small 

 tubercles, between which are numerous microscopic granules. The apical system is elongated. 

 The four genital plates are large and distinctly perforated. The anterior, right-hand genital 

 plate, which serves as the madreporite, is much larger than any of the others, being several times 

 the size of the anterior left-hand genital, with which it is in contact. The posterior genitals are 

 very nearly of equal size. 



The peristome is transversely oblong and situated near the anterior margin. The periproct 

 is oval and situated on a marked protuberance on the posterior margin. 



Locality. — Vincentown, N. J. 



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



Collection. — Johns Hopkins University (T 3011). 



Ananchytes texana Cragin. 

 Plate XXXV, figures.2a-c; Plate XXXVI, figures la-b. 



Ananchytes texana Cragin, 1893, Geol. Survey Texas Fourth Ann. Rept., pp. 145, 146, PL XXVI, figs. 1, 2, PI. XXV, 

 fig. 12. 



Determinative characters. — Test large, high, oval in marginal outline, rounded anteriorly, 

 narrowed posteriorly; upper surface convex, lower surface flat; ambulacra flush, nearly alike, 

 apetalous pair of pores more strongly developed on upper surface; interambulacra with large 

 plates covered with few primary tubercles and many granules; peristome far in front; periproct 

 well forward on lower surface. 



Dimensions. — Length 107 millimeters; width 87 millimeters; height 68 millimeters. 



Description. — Cragin says : l 



Large conico-hemispherical as seen from the" side; plan ovate, wider anteriorly; peristome of moderate size, trans- 

 verse, oblong-reniform, the anterior lip and immediately contiguous surface deeply and abruptly depressed, the 

 remainder of the interior surface slightly depressed, the depression being posteriorly parted by a gentle median undu- 

 lation that includes the periproct and becomes gradually obsolete a short distance in advance of it; periproct infra- 

 marginal and relatively smaller than in most (if not all) other known species of the genus, rather narrowly ovate and 

 posteriorly more or less pointed; anterior ambulacrum about two-thirds as wide as either of the adjacent interambula- 

 cra, ambulacral plates very numerous and narrow, averaging about a millimeter in width on the greater part of the zone ; 

 the pores rounded but usually more or less transversely elongated, the line connecting the pores of one pair being hori- 

 zontal except in the case of a few of the lower pairs; surface nearly even, the principal tubercles rather small and not 

 very prominent. 



Locality. — Two and one-half miles northwest of D'Haniss, on Seco Creek, Medina County, 

 Tex. (type); White Cliffs, Ark. 



Geologic horizon. — Austin chalk and Annona chalk, Upper Cretaceous. 

 Collections. — Geological Survey of Texas; Johns Hopkins University. 



