Klem — Revision of the Palaeozoic Palaeechihnoidea. 19 



1875. Perischodomus hiserialis. Quenstedt, Petrefact. 

 Deutschl., bd. 3, abth. 1, p. 374, tab. 75, fig. 13. 



1876. Perischodomus hiserialis. Keeping, Quart. Joum. 



Geol. Soc, vol 32, pt. 1, p. 36, pi. 3, figs. 1-5. 

 1896. Perischodomus hiserialis. Jackson, Bull. Geol. Soc. 

 Amer., vol. 7, p. 226. 

 Interambulacra consist of five columns of irregular, very 

 finely granulated plates. Adambulacral plates bear small, 

 mammillated, perforated, primary tubercles. Two columns 

 of small plates in each ambulacrum. 



Geological formation and locality : Lower Carboniferous, 

 Hook Head, Wexford, England. 



2. Perischodomus hartei Baily. 



1864. Harte, Dub. Quart. Journ. Sci., vol. 



5, p. 265, pi. 9. 

 1864. Harte, Journ. Roy. Geol. Soc. Ireland, 



ser. 2, vol. 1, pt. 1, p. 67, pi. 5. 



1874. Archaeocidaris Harteiana. Baily, Journ. Geol. Soc. 

 Ireland, n. s. vol. 4, pt. 1, p. 42, pi. 4, figs. a-c. 



1875. Quenstedt, Petrefact. Deutschl., vol. 



1, p. 379. 



1875. Archaeocidaris Harteiana. Baily, Char. Brit. Foss., 



vol. 1, p. LXVIII. 



1881. Perischocidaris Hartei. Neumayr, Sitzb. K. Akad. 



Wiss. Wien, Math.-Naturw. CI., Bd. 84, Abth. 1, p. 



174, taf. 1, fig. 7. 

 1892. Homotoechus Hartii. Sollas, Scient. Proc. Roy. Dub. 



Soc, u. s. vol. 7, pt. 3, p. 153. 

 Genital plates have each a large perforated tubercle, sur- 

 rounded by a depressed ring, which is further surrounded by 

 sixteen pores. Adambulacral plates bear tubercles on the 

 first, second, fourth and seventh, while the third, fifth and 

 sixth plates are plain. Ambulacra large , pores in two depres- 

 sions, with three pair of pores in each ambulacral depression. 

 One small tubercle on each ambulacral plate. 



Geological formation and locality: Yellow sandstone, 

 Donegal, Ireland. 



