Klem — Revision of the Palaeozoic Palae'echinoidea. 29 



1894. Palaechinuselegans. Tornquist, Mitth. Geol, Landes- 

 anst. Elsass. Bd. 4, p. 100. 



1896. RJioecJdniis elegans. Jackson, Bull. Geol. Soc. 

 Amer., vol. 7, p. 205, pi. 7, fig. 40. 



1897. Rhoechinus elegans. Tornquist, Abhdl. Geol. Spe- 

 cialkarte Elsass. Loth., Bd. 5, lift. (3, p. 757, taf. 20, 

 figs. 10, 11, 12, taf. 21, fig. 6. 



General shape ovate. Interambulacra composed of five 

 columns each of mammillated plates, covered with very 

 minute tubercles. Ambulacra large and convex. The lateral 

 interambulacral plates equal five ambulacral plates in width. 



Geological formation and locality : Carboniferous Lime- 

 stone, Hook Head, Fethard, Wexford, England. 



3. Rhoechinus gracilis Meek and Worthen. 



1869. Palaechinus gy^acilis. Meek and Worthen, Proc. 

 Acad. Nat. Sci. Phil., p. 82. 



1873. Palaechhius gracilis. Meek and Worthen, Geol. 

 Surv. 111., vol. 5, p. 473, pi. 10, fig. 2. 



1874. Palaechinus gracilis. Loven, Kongl. Svens. Vetens. 

 Akad. Handl., Bd. 11, no. 7, p. 41. 



1889. Palaechinus gracilis. Miller, N. Amer. Geol. Pal., 

 p. 266. 



1895. Palaechinus gracilis. Keyes, Proc. Iowa Acad. Sci., 

 vol. 2, p. 180. 



1896. Rhoechinus gracilis. Jackson, Bull. Geol. Soc. 

 Amer., vol. 7, p. 201, pi. 7, figs. 36, 37. 



Body small. Seven columns in each interambulacrum. 

 Plates ornamented with fine granules. Ambulacra wide in 

 proportion, slightly convex, composed of very short pieces. 

 Two pores at the outer end of each piece, arranged in two 

 ziszas: rows alons: the lateral margins of each ambulacral 

 area. Plates ornamented with fine granules. 



Geological formation and locality : Burlington Limestone, 

 Burlington, Iowa. Waverly Group, Bever Creek, Menifee 

 Co., Ky. 



