84 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES. 



The apical system is narrow, elongated. The four perforated genital plates are disposed in 

 pairs, between which two of the five ocular plates are situated. Forming the posterior portion 

 of the disk are two more ocular plates, while the fifth plate comprises the anterior part. The 

 ambulacral areas are on this account separated at their apices. 



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

 The periproct is oval and situated on the truncated surface at the posterior margin of the test. 



Localities. — Vincentown and Timber Creek, N. J. 



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



Collections. — Academy of Natural Sciences of Philadelphia (1485); American Museum of 

 Natural History, New York. 



Cardiaster smocki Clark. 



Plate XXXVI, figures 3a-c. 



Cardiaster smocki Clark, 1907; Weller, Cretaceous paleontology of New Jersey: Geol. Survey New Jersey, p. 298, PI. 

 XIII. figs. 9-11. 



Determinative characters. — Test cordiform, elevated, with deep anterior sulcus; upper sur- 

 face convex; lower surface flat. Ambulacra wide. Apical system elongated. Peristome near 

 the anterior margin. 



Dimensions. — Length 25 millimeters; width 23 millimeters; height 14 millimeters. 



Description. — The test is small, distinctly elevated, with strongly convex upper surface. 

 The anterior ambulacral sulcus is very pronounced, and the opposite ridge in the unpaired pos- 

 terior interambulacrum is well shown but is sharply cut off by the nearly vertically truncated 

 surface of the posterior margin. The sides slope rapidly to the ambitus, which is sharp and cor- 

 date in outline. The lower surface is nearly flat. 



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

 are bent backward above, beyond which they extend straight to the ambitus. The postero- 

 lateral pair are bent slightly forward, beyond which they continue in a straight line over the 

 margin. The unpaired ambulacrum is situated in the deep anterior sulcus. 



The apical system is much elongated, widely separating the ambulacral areai. 



The peristome is situated anteriorly and is transversely oval. 



Related forms. — This species is most closely related to Cardiaster cinctus but is smaller and 

 has a somewhat less pronounced anterior sulcus and a more inflated test. 



Locality. — Two and a half miles northwest of Matawan, N. J. 



Geologic horizon. — Merchantville clay of Matawan group, Upper Cretaceous. 



Collection. — Geological Survey of New Jersey. 



Cardiaster cttrtus Clark, n. sp. 

 Plate XXXVII, figures la-h. 



Determinative characters. — Test small, cordate, high anteriorly, clearly marked anterior 

 groove with well-defined keel on either side; ambulacra wide, interambulacra with large plates; 

 peristome near posterior margin. 



Dimensions. — Length 22 millimeters; width 19 millimeters; height 12 millimeters. 



Description. — The two specimens of this small species are fragmentary although retaining 

 the most important characteristic portions. 



The test is cordate, elevated toward the posterior margin and with broad and deep anterior 

 groove. The ambulacra are broad, the poriferous zones are clearly marked on the upper sur- 

 face. The pore pairs are oval above and more nearly round toward the ambitus. The surface 

 of the plates is covered by minute granules. 



The interambulacra are composed of large plates covered with minute granules. 



The apical system is elongate, the four genitals varying in shape and size. The two antero- 

 lateral oculars are very large and separate the antero-lateral from the postero-lateral genitals 

 which are in contact, the latter isolating the two postero-lateral oculars from the remainder of the 

 apical system. 



