PLATE 68. 



Lepidesthes laevis Trautschold. Page 4 IS. 



Fig. 1. Lower Carboniferous, Moscow, Russia. Museum fur Naturkunde, Berlin. X 1.2. Six columns of ambulacra! 



plates and a section showing adoral imbrication of same. 

 Fig. 2. Same specimen, one ambulacral plate enlarged. 



Lepidesthes formosa Miller. Page 418. 



Figs. 3-14. Kaskaskia Group, Lower Carboniferous, Pulaski County, Kentucky. 



Fig. 3. Same specimen as photograph, Plate 66, fig. 7. X 4.8. Orally teeth and pyramids are in place. Ambulacra! 

 plates only on the peristome. Four columns of ambulacral plates in area B ventrally, increasing to eight columns 

 aborally; all imbricate ventrally. Primordial interambulacral plates in the basicoronal row, two plates in the 

 second, three in the third, and four in the fourth row. Interambulacral plates imbricate dorsally and laterally. 



Figs. 4-7. Univ. of Chicago Mus. Coll. Same specimen as photographs, Plate 66, figs. 4 and 5. Holotype. 



Fig. 4. Segment at the mid-zone. X 4.8. Eight columns of plates in each ambulacral area and five columns of plates 



in each interambulacral area. 

 Fig. 5. Dorsal portion of test. X 4.6. Ambulacra with one or two plates next the oculars, increasing in number passing 



ventrally. Interambulacral columns all extend to the apical disc, young plates being in contact with the oculars. 



Oculars (shaded) are all insert with two pores, a remarkable feature (pp. 89, 413). Madreporite with two genital and 



madreporic pores (p. 172). Genitals 1 and 5 have three pores each. Periproct with angular, thin plates, 

 Fig. 6. Section at mid-zone. X 4.6. To show beveling of interambulacral plates; ambulacral plates shaded. 

 Fig. 7. Isolated ambulacral plate, to show the dorsal and ventral bevel. X 4.6. 



Figs. 8, 9. Chicago Univ. Coll., 6,604. Same specimen as photograph, Plate 66, fig. 6. Paratype. 



Fig. 8. Genital plate, with three pores. X 2.4. 



Fig. 9. Two pyramids. X 2.3. In 6, tooth in place, seen from exterior; in a, the tooth, seen from the interior, is grooved. 



Figs. 10-15. Sloan's Valley, Pulaski County, Kentucky. F. Springer Coll. 



Fig. 10. Springer Coll., 8,023. Pyramid, with tooth in place, restored ventrally, as indicated by dotted lines. X '2.3. 



Epiphyses wanting; foramen shallow. The inner aspect and section of the tooth are drawn from another specimen, 



which is in the Springer Coll., 8,023. 



Fig. 11. Springer Coll., 8,027. Upper part of a left and right half-pyramid with epiphyses in place. X 2.2. 

 Fig. 12. Springer Coll., 8,033. Pyramid, in side view, with ridges for the attachment of the interpyramidal muscle and 



an epiphysis, showing the tubercle, lu., and glenoid cavity, gl., for articulation with the brace. X 4.7. (Compare 



Plate 2, fig. 7.) 



Fig. 13. Springer Coll., 8,043. Brace, with epiphyses, the latter restored, as indicated by dotted lines. X 4.7. 

 Fig. 14. The same specimen, face view, showing the brace resting against the epiphysis of the right half-pyramid, but 



the epiphysis is wanting in the left half-pyramid. X 4.6. 



Lepidesthes devonicans Whidborne. Page 420. 



Figs. 15-17. Devonian, Pilton Beds, North Devon (after Whidborne, 1898, Plate 25, figs. 3a, 3b, and 3e). Museum of 

 Practical Geology Coll., London, 7,160, and 7,161, counterparts, holotype. 



Fig. 15. From a wax cast of ambulacral plates showing pore-pairs. X 3. 

 Fig. 16. From a wax cast of interambulacral plates, showing tubercles. X 3. 

 Fig. 17. Spine. X 6. 



Lepidesthes coreyi Meek and Worthen. Page 423. 



Figs. 18-22. Keokuk Group, Lower Carboniferous, Crawfordsville, Indiana. 



Fig. 18. Same specimen as photograph, Plate 66, fig. 8. Segment at the mid-zone. X 2.3. Ten columns of plates in the 



ambulacral area and at this zone five columns of plates in the interambulacral area. 

 Fig. 19. Same specimen. X 2.2. Ambulacral plates with tubercles and spines. 

 Fig. 20. Same specimen. X 2.4. Interambulacral plates with tubercles and spines. 

 Fig. 21. Yale Mus. Coll., 317. Spines tapering, swollen at the base, longitudinally finely striate. X 4.9. From a very 



large specimen, about 75 mm. high. 

 Fig. 22. Freiburg, i. B., Museum. Enlarged. Base of the test with the lantern in place. 



Figs. 1, 2, and 22 after my sketches; figs. 15-17 after Whidborne by W. M. Barrows; all others figs, by J. Henry Blake. 



