458 ROBERT TRACY JACKSON ON ECHINI. 



Palaechinus carpenteri Dollo and Buisseret, 1888, p. 959. 

 No description of this species has been published. 



Palaechinus loveni Dollo and Buisseret, 188S, p. 959. 

 No description of this species has been pubhshed. 



Palaeozoic Forms Incorrectly Referred to Echini. 



DiscocYSTis Gregory, 1897, p. 131; Klem, 1904, p. 73. 

 Echinodisrits Worthen and Miller, 1S83, p. 3.35, non Echinodiscus Leske, 1778, p. 131; Klem, 1904, p. 73. 



The name Discocj'stis was given by Gregory to replace the name Echinodiscus, which 

 was preoccupied. 



Discocystis kaskaskiensis (Hall). 



Agclncrinus kaskaskiensis Hall, 1858, p. 696, Plate 25, fig. 18. 



Echinodiscm kaskaskictisis Keyes, 1894, p. 133, Plate 18, fig. 3; Klem, 1904, p. 73. 



Discocystis optatus (Worthen and Miller). 



Echinodiscus optafus Worthen and Miller, 1883, p. 336, Plate 31, fig. 9; Klem, 1904, p. 73. 



Discocystis sampsoni (Miller). 



Echinodiscus sampsoni Miller, 1891, p. 76, Plate 12, fig. 16; 1892, p. 686, Plate 12, fig. 16; Keyes, 1894, 

 p. 133; Klem 1904, p. 73. 



The above considered species referred to Discocystis I think are all Cystoidea, but they 

 were referred doubtfully to Echini by Miss Klem (1904, p. 73); and the genus Discocystis also 

 was qualifiedly compared to Echini by Gregory (1897, p. 131). 



Myriastiches Sollas, 1899, p. 700; Klem, 1904, p. 74; Lambert and Thiery, 1910, p. 117. 

 Genotype, M. gigas Sollas. 



Myriastiches gigas Sollas, 1899, pp. 700, 701, text-fig. 5; Klem, 1904, p. 74; Lamhert and Thiery, 1910, 

 p. 117. 



Of doubtful nature; the described material is in the University Museum, Oxford. 



Palaechinus sp. Mitchell, 1897, p. 258, text-fig.; Klem, 1904, p. 36. 

 Of doubtful nature; Silurian, New South Wales. 



Spatangopsis Torell, 1869, p. 11; Klem, 1904, p. 75. Genotype, S. costata Torell. 

 Spatangopsis costata Torell, 1869, p. 11; Zittel, 1879, p. 480; Klem, 1904, p. 75. 



The genus Spatangopsis is not an echinoid, but a medusoid according to Zittel (Grund- 

 ziige der Palaeontologie, p. Ill) and other authorities. 



