PLATE 19. 

 Koninckocidaris silurica sp. nov. Page 285. 



Fig. 1. From base of Rochester Shale, about ten feet above the Irondequot Limestone. Niagara Group, Upper Silurian, 

 ravine of the Genesee River, northern part of Rochester, New York. A. W. Giles, collector, 1909. Rochester Uni- 

 versity Coll. Holotype. Natural size. Of special interest as by far the geologically oldest echinoid yet found in 

 America. Test viewed from the interior, ambulacral plates are high, about three equaling the height of an adam- 

 bulacra! plate. Ambulacral plates bevel over the interambulaerals and imbricate dorsally, as this is an internal 

 view. Pores are near the middle of the ambulacral area, a quite usual character of the interior. Eight columns of 

 nearly rhombic plates in an interambulacral area, all of which extend to the apical disc. All interambulacral plates 

 imbricate ventrally and toward the center, nearly covering column 7, which shows only as very narrow plates. This 

 is because it is an internal view. (For imbrication and beveling of ambulacral and interambulacral plates seen from 

 the interior and exterior, see text-figs. 32-37, p. 75.) Drawings, Plate 20, figs. 5, 6. 



Lepidocentrus miilleri Schultze. Page 289. 



Fig. 2. Middle Devonian, Muhlenberg, near Gerolstein, Prussia. Mus. Comp. Zodl. Coll., 3,040 (from F. Sehultze Coll.), 



holotype. Natural size. Ambulacra narrow, plates low. Interambulacrum A with 11 columns of nearly rhombic 



plates imbricating dorsally and from the center laterally. Columns 5, 6, 9, 10, and 11 of area A drop out dorsally. 



Drawings, Plate 20, figs. 8-10. 

 Fig. 3. Middle Devonian, Gerolstein, Prussia. Palaeontological Museum, Munich. Natural size. Interambulacral 



plates nearly rhombic, imbricating strongly; small primary and secondary tubercles and some spines in place. These 



two figs. (2, 3) are the most nearly complete specimens known in the species. 

 Fig. 4. A plate from the same specimen, to show a perforate eccentric primary tubercle with scrobicule and secondary 



tubercles. X 3. 

 Fig. 5. Same specimen, a, secondary spine, X 5, and b, primary spine, X 5; c, secondary spine, X 10. The spines 



are enlarged at the base, vertically very finely striate, nearly cylindrical as far as shown, but complete spines taper 



to a point distally. 



Lepidocentrus whitfieldi sp. nov. Page 290. 



Fig. 6. Waverly Group, Lower Carboniferous, Licking County, Ohio. Amer. Mus. Nat. Hist. Coll., 6,391, holotype, 

 Natural size. Ventral view, about spherical in form, but flattened ventrally, ambulacral areas narrow Drawing. 

 Plate 21, fig. 4. 



Fig. 7. Same specimen, dorsal view. Drawing, Plate 21, fig. 5. 



Hyattechinus pentagonus sp. nov. Page 295. 



Fig. 8. Waverly Group, Lower Carboniferous, Meadville, Pennsylvania. Mus. Comp. Zool. Coll., 3,108 (from R. T. J. 

 Coll.), paratype. Natural size. External sandstone mold of the dorsal side; ambulacra narrow, fourteen columns 

 of plates in each interambulacrum. The apical disc measures about 9 mm. in diameter, and the test about 57 mm. 

 in diameter. The apical disc therefore measures proportionately about 16 % of the diameter of the test. 



Figs. 1, 2, S from photographs by H. W. Tupper; figs. 6, 7 by F. A. Saunderson; figs. 3-5 drawn by Anton Birkmaier. 



