Klem — Revision of the Palaeozoic Palae'echinoidea. 15 



1. BoTiiRiociDARis GLOBULUS Eichwald. 



1860. Bofhriocidaris globulus. Eichwald, Lethaea Ross. anc. 



Per., p. 655, taf. 32, fig. 22 a, b. 

 1874. Bothriocidaris globulus. Schmidt, Mem. Acad, Imp. 



Sci. St. Petersbourg, serie 7, tome 21, no. 11, p. 37. 

 1894. BotJiriocidaris globulus. Jaekel,Sitz. Gesell. Naturfor. 



Freunde, Berlin, p. 245. 

 Each ambulacra] plate bears four perforated spines, and 

 each interambulacral plate from one to three perforated 

 spines. The genital plates are separated by the ocular 

 plates. 



Geological formation and locality: Silurian, Dago, Russia. 



2. BoTHRiociDARis PHALENi Schmidt. 



1874. Bothriocidaris Phaleni. Schmidt, ISlem. Acad. Imp. 

 Sci. St. Petersbonrg, serie 7, tome 21, no. 11, p. 34, 

 tab. 4, figs. 1 a-g. 



1892. Bothriocidaris Phaleni. Agassiz, Mem. Mus. Comp. 

 Zool., vol. 17, no. 2, p. 72, pi. 29, fig. 1. 



1894. Bothriocidaris Phaleni. Jaekel, Sitzb. Gesell. Natur- 

 for. Freunde, Berlin, p. 246. 

 Each ambulacral plate bears two perforated spines. No 



spines on the interambulacral plates. The five genital plates 



are in contact with each other. 



Geological formation and locality: Lower Silurian, 



Nommis, Russia. 



C. PERISCHOECHINOIDA M'Coy 1849.* 



Syn. Tessellati Desor 1858. f 



Body round or elliptical. More than two columns of plates 

 in the interambulacrum (sometimes also in the ambulacrum). 



* Ann. Mag. Nat. Hist. (2), vol. 3, p. 251. 

 t Synopsis des Echinides 1858, p. 152. 



