PLATE 69. 

 Lepidesthes colletti White. Page 425. 



Fig. 1. Keokuk Group, Lower Carboniferous, Montgomery County, Indiana. Mus. Comp. Zool. Coll., 3,178 (from R. T. 

 J. Coll.). Enlarged X 1.6. Height of the specimen 44 mm. through the axis III, 5. A very complete specimen, 

 oriented by the presence of the madreporite with its typical pores. There are few plates in an ambulacral area 

 dorsally near the apical disc but they increase to sixteen columns of plates in each ambulacral area at the mid-zone. 

 Four columns of plates in each interambulacrum; oculars, genitals, and periproctal plates in place. The apical disc 

 is small, measuring proportionately about 16 % of the diameter of the test. Drawings, text -fig. 251, p. 428; Plate 

 71, fig. 1 (p. 428). 



Fig. 2. Keokuk Group, Lower Carboniferous, Salem, Washington County, Indiana. Univ. of Chicago Coll., 6,340. This 

 is the specimen figured by White, 1880a, Plate 40, figs. 2, 2a. Natural size. A small specimen, but it shows sixteen 

 columns of plates in an ambulacral area above the mid-zone and four columns of plates in an interambulacral area (p. 

 428). 



Fig. 3. The same specimen, enlarged. X nearly 1.8. 



Fig. 4. Keokuk Group, Lower Carboniferous, Bono, Indiana. Univ. of Chicago Coll., 6,641. Natural size. Not dis- 

 torted, and showing the typical elliptical form of this species, sixteen columns of plates in an ambulacral area and 

 four columns of plates in each interambulacral area at the mid-zone. Ambulacral Plates are narrow hexagons at 

 the mid-zone. Drawing, Plate 70, fig. 2 (p. 428). 



Fig. 5. Keokuk Group, Lower Carboniferous, Montgomery County, Indiana. F. Braun Coll. Natural size. Small 

 specimen partly embedded in the rock, very well preserved, shows periproctal plates dorsally. There are sixteen 

 columns of plates in an ambulacral area and four columns of plates in each interambulacral area (p. 429). 



Fig. 6. Keokuk Group, Lower Carboniferous, Montgomery County, Indiana. Mus. Comp. Zool. Coll., 3,177 (from R. T. 

 J. Coll.). Natural size. Specimen uncompressed, of natural shape; teeth are seen ventrally; details of the coronal 

 plates are very complete, especially at the mid-zone and dorsally. Ambulacral plates at the mid-zone are rhombic 

 in outline, whereas in the larger specimens, figs. 7 and 8, they are hexagonal in outline at the mid-zone. Drawing, 

 Plate 70, fig. 1 (p. 429). 



Fig. 7. Keokuk Group, Lower Carboniferous. Montgomery County, Indiana. Mus. Comp. Zool. Coll., 3,176 (from R. T. 

 J. Coll.). Enlarged X about 1.3. The specimen is very large, measuring 70 mm. in height. Details of the plates 

 arc very clear. Sixteen columns of plates in an ambulacral area and four columns of plates in an interambulacral 

 area at the mid-zone, but in area A a fifth column is introduced 14 mm. below top of the specimen, the only case of a 

 fifth column seen in the species. This specimen shows well the low hexagonal form of ambulacral plates at the mid- 

 zone, which is characteristic of large individuals, but dorsally the plates are rhombic in form as are all the ambulacral 

 plates of a younger individual. Drawings, Plate 70. figs. 3 and 4 (p. 429). 



Fig. 8. Keokuk Group, Lower Carboniferous, Montgomery County, Indiana. Mus. Comp. Zool. Coll., 3,179 (from R. T. 

 .L Coll.). Natural size. A very large and perfect specimen measuring 70 mm. in height, details of the plates ex- 

 ceptionally clear. Sixteen columns of plates in an ambulacral area at the mid-zone, four columns of strongly im- 

 bricating plates in each interambulacral area. In this specimen, as well as in fig. 7, the ambulacral plates are hexagonal 

 in form at the mid-zone, whereas in younger specimens, figs. 4—6, they are rhombic at the mid-zone. As a localized 

 stage dorsally, however, in this large specimen the younger ambulacral plates dorsally are rhombic in form as a 

 localized stage in development (p. 430). 



