INCERTAE SEDIS. I.-,.-', 



Palaeocidaris exilis Eichwald. 

 Text-fig. 254. 



Palaeocidaris exilis Eichwald, 1854, p. 114, Plate 2, fig. 14. 

 Bothriocidaris exilis Eichwald, 1860, p. 656. 



A small unrecognizable mass. In general, it is spheroidal in form, and has numerous smal 

 elevations which Eichwald considered to be tubercles. 

 Pentamerous Limestone, Silurian, of Talkhof, Russia. 



Palaeodiscus gothicus Wyville Thomson. 



Palaeodijicus gothicus Wyville Thomson, 1861, p. 118, Plate 4, fig. 8; Lambert 

 and Thiery, 1910, p. 117. 



This species is unrecognizable. 



Lower Ludlow Flags, Silurian, Leintwardine, Shropshire, England. 254 



TEXT-FIO. 254. Palaeoci- 



Palaeospatangus skiptoni Harte. dariM *"*" Eichwal d. Ho!o- 



type. Natural size and en- 



Palaeospatangus skiptoni Harte, 1869, pp. 135, 136. larged ' After EichwaU , 1854 . 



Plate 2, fig. 14. 



Described as spatangoid in shape, but no recognizable description 



is given. All data are doubtful, but Harte thought that the specimen came from the Lower 

 Carboniferous Sandstone of Scotland. 



Perischodomus magnus Tornquist. 

 Prrischodomus magnus Tornquist, 1893, p. 103; Klem, 1904, p. 20. ' 



Described from a single interambulacral plate which bears a primary and secondary 

 tubercles. The status of the species is doubtful as well as its generic reference. 

 Lower Carboniferous, Upper Alsace, Germany. 



PROTOECHINUS T. Austin. 



Protocchinus T. Austin, 1860, p. 446; Loven, 1874, p. 42; Jackson, 18%, p. 235; Klem, 1904, p. 75. 



Palaeechinus (pars) Duncan, 1889a, p. 13. 

 Melonechinus (pars) Lambert and Thie"ry, 1910, p. 120. 



Ambulacra with two columns of plates, and passing toward the wider portion of the area 

 with intercalated plates added, producing four columns. There is a pore-pair in each plate. 

 The interambulacrum is fragmentarily known, and other parts of the test are unknown. 



Type species, P. anceps Austin, from the Lower Carboniferous of Ireland. 





