152 



PELTASTES. 



Peltastes stellulatus, Agassiz] 1846. PI. XXXI, figs. 1, 2, 3 ; PI. XLI, fig. 1 a—g. 



Salenia stellulata, 



Agassiz. Monog. des Sale'nies, pi. ii, figs. 2.5 — 32, p. 



15, 1838. 

 Agassis. Ibid., pi. in, figs. 1 — 8, p. 16. 

 Agassiz. Echin. foss. de la Suisse, pi. xxiii, figs. 6 — 10, 



p. 90, 1840. 

 Agassiz. Ibid., figs. 11 — 15, 1840. 

 Agassiz et Desor. Cat. raison. des Echinides, Ann. Sc. 



Nat, 3e ser., torn, vi, p. 342, 1846. 

 Agassiz et Desor. Ibid. 

 — Marcou. Jura salinois, Me'm. Soc. Geol. de France, 2e ser., 



t. iii, p. 140, 1848. 

 pentagonifera, A.Gras. Ours. foss. del'Isere, p. 29, pi. i, figs. 11,12,1848. 



— areolata, 



— stellulata, 



areolata, 



Peltastes stellulatus, 



— punctata, 



Salenia stellulata, 

 Peltastes — 



— punctata, 

 Peltastes stellulata, 



Hyposalenia — 



— punctata, 



Peltastes stellulata, 



punctata, 



— pentagonifera, Pictet 



— Courtaudina, Pictet 



— stellulata, 



Hyposalenia — 

 Peltastes stellulatus. 



Bronn. Index Palaeontologicus, p. 1008, 1849. 



D'Orbigny. Prod, de Paleont. strat., t. ii, p. 89, 1850. 



D'Orbigny. Ibid. 



Cotteau. Catal. des Echinid. neocomiens, 1851. 



Bronn. Leth. Geognost., Kreidegeb., pi. xxix, fig. 5, 1852. 



Desor. Synops. des Echinid. foss., pi. xx, figs. 6 — 8, 1856. 



Desor. Ibid. 



Traite' de Paleont., 2e ed., t. iv, p. 248, 1857. 



Ibid. 



Ibid. 



Ibid. 

 Leymerie et Raulin. Geol. de I'Yonne, Stat. geol. du dep. 



de I'Yonne, p. 420, 1858. 

 Leymerie et Raulin. Ibid. 



Cotteau. Ech. foss. de I'Yonne, pi. 54, figs. 1—10, 1859. 

 Cotteau. Paleontol. Fran9aise; Terrain Cretace, pi. 1023, 

 p. lOQ, 1862. 



Pictet. 

 Pictet. 



Diagnosis. — Test small, circular, convex above, flat below, poriferous zones straight, 

 formed of oblique pairs, ambulacra straight, two rows of homogeneous mammillated 

 granules, set closely together, fourteen in each row. Inter-ambulacra wide, two rows of 

 tubercles, five in a row, unequal in size, large at the ambitus, and small near the base ; 

 apical disc very large, round, and depressed ; sutures well marked with isolated points, and 

 fine incisions ; madreporic fissure small, distinct, and surrounded by an elevation of 

 the plate. 



Dimensions. — Height three tenths of an inch ; transverse diameter half an inch. 



Description. — The table of synonyms affords evidence how changes of form in certain 

 parts of an Urchin lead to confusion in the identification of the species, and how impossible 

 it is to define in a few words certain organisms among which the same structures vary much 



