214 MESOZOIC AND CENOZOIC ECHINODEKMATA OF THE UNITED STATES. 



posterolateral. The pore pairs are large and not numerous. They appear again on the lower 

 surface near the peristome. 



The interambulacra are narrow above and widen rapidly. They have numerous large 

 tubercles below which become few and irregularly scattered above the lower margin. The 

 fasciole can be plainly traced. 



The apical system is small. The peristome is large and slitlike, very much elongated 

 transversely. The periproct is moderate in size, high on the posterior truncation. 



Locality. — James River, Va. 



Geologic horizon. — Yorktown formation, upper Miocene. 



Collections. — Academy of Natural Sciences of Philadelphia (1079); American Museum of 

 Natural History; U. S. National Museum: Johns Hopkins University (T. 1002). 



Echinocardium DEPREssuM Clark, n. sp. 

 Plate XCVIII, figures 3a-c. 



Determinative characters. — Test moderate, cordiform, low, depressed, both upper and 

 lower surfaces nearly flat, anterior groove shallow, posterior truncation. Ambulacra wide, 

 anterior in shallow groove, paired in grooves, triangular in outline, open above, narrow below. 

 Interambulacra narrow above, widening rapidly toward the ambitus. Peristome small. 



Dimensions. — length 40 millimeters; width 37 millimeters; height 13 millimeters. 



Description. — This species is represented only by casts, which, however, are very different 

 in their characters from E. orthonotum, the only other Miocene representative of this genus from 

 American deposits. The test is of moderate size, cordiform, low, much depressed, nearly flat. 

 The anterior groove is shallow and broad. The posterior margin is truncated. 



The ambulacra are wide, the paired ambulacra being situated in shallow grooves triangular 

 in outline. They are open above and narrow below. The interambulacra are narrow above, 

 forming a very obtuse angle, but widening rapidly below toward the ambitus. The fascioles 

 are absent. The peristome is small and apparently transversely elongated. 



Locality. — Near old Chattahoochee Landing, Apalachicola River, Fla. 



Geologic horizon. — Lower Miocene. 



Collection. — U. S. National Museum (164454). 



Echinocardium gothicus (Ravenel). 



Amphidetus gothicus Ravenel, 1848, Echinidse, recent and fossil, South Carolina, p. 4 and figure. 

 Amphidetus ampliphorus McCrady, 1855, Pliocene fossils, South Carolina, pp. 7, 8, PI. II, fig. 2. 

 Amphidetus gothicus McCrady, 1855, Pliocene fossils, South Carolina, pp. 7, 8, PI. II, fig. 3. 

 (?) Echinocardium cordatum A. Agassiz, 1872, Revision of the Echini, pt. 1, pp. 109, 110. 

 Amphidetus gothicus A. Agassiz, 1874, Revision of the Echini, pt. 4, p. 751. 

 Echinocardium ampliflorus, Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 707. 

 Echinocardium gothicum Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 707. 



Description. — No material has been secured and it is therefore impossible to satisfactorily 

 describe this species. A. Agassiz regards E. gothicus and E. ampliphorus as the same species 

 and refers it doubtfully to E. cordatum, which is found widely distributed in the Atlantic Ocean 

 to-day. 



Locality. — The Grove, Cooper River, S. C. 



Geologic horizon. — Duplin marl, upper Miocene. 



Collection . — Unknown . 



Genus LINTHIA Merian. 



Linthia? californica Weaver. 



Plate XCVIII, figure 4. 



Linthia (?) californica Weaver, 1908, Univ. California Dept. Geology Bull., vol. 5, No. 17, pp. 272, 274, PI. XXI, fig. 2. 

 Brissopsis californica Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 705. 



