PLATE 27. 



Pholidechinus brauni sp. nov. Page 299. 



Figs. 1-6. Keokuk Group, Lower Carboniferous, Crawfordsville, Indiana. 



Fig. 1. Mus. Comp. Zool. Coll., 3,109, (from R. T. J. Coll.) holotype. Natural size. Ambulacra narrow throughout. 

 Nine columns of plates in both interambulacral areas at the mid-zone, but a tenth column exists dorsally in area C. 

 Tubercles and some spines are clear in both ambulacra! and interambulacral areas of this specimen. Drawings. Plate 

 28, figs. 2, 9. 



Fig. 2. F. Braun Coll., paratype. Natural size. Nine columns of plates in interambulacra A and I. Teeth in place, 

 and ambulacral plates only on the peristome. Drawing, Plate 28, fig. 1. 



Fig. 3. British Mus. Coll., E 10,678 (from R. T. J. Coll.), paratype. Natural size. A tenth column originates in inter- 

 ambulacrum A earlier than in fig. 1. Drawings, Plate 28, figs. 4-(3. 



Fig. 4. Yale Mus. Coll., 321, paratype. X 3. This figure with figs. 5, 6, represents the most perfect lantern known in a 

 Palaeozoic echinoid. Teeth in place. Peristome in part in place on the lantern, consisting of low. wide imbricate 

 ambulacral plates only. The pyramids are wide-angled, producing as a consequence a wide and flaring lantern 

 which is largely visible from this ventral view. There are wide outwardly curving spaces for long interpyramidal 

 muscles (compare Plate 2, figs. 19, 20) ; the outer ends of the epiphyses, braces, and in area D a compass are visible 

 in this view. 



Fig. 5. Same specimen, dorsal view. X 3. Five teeth nearly or quite in place and in line with the pyramidal sutures. In 

 areas B, J, H, and F, narrow epiphyses and braces are in place. In area D, a compass also exists, though slightly 

 displaced; distally it is not bifurcate, probably due to wear. 



Fig. (5. Same specimen, profile view. X 3. The lantern is inclined at an angle of about 45, foramina magna moderately 

 deep. Teeth visible ventrally and just above the foramina dorsally, narrow epiphyses are in place, capping the half- 

 pyramids; braces are in place between the epiphyses, and the compass is just visible in area D. In area F, a wide 

 space exists between the pyramids for a long interpyramidal muscle. (Compare Plate 2, fig. 19, and text-fig. 207, 

 p. 184.) 



Photographs by F. A. Saunderson; drawings of the lantern by J. Henry Blake. 



