TRIGONTA. 79 
1850. Triconta rupis, A. d’Orbigny. Prodr. de Pal., vol. ii, p. 78 (? partim). 
1854. — novosa, J. Morris. Cat. Brit. Foss., ed. 2, p. 229. 
? 1855. — RUDIS, Gr. Cotteau. Moll. Foss. de l’Youne, p. 76. 
1857. — DADALEA, I’. J. Pictet and TL. Renevier. Foss. Terr. Aptien 
(Mater. Pal. Suisse, ser. 1), p. 92, plexi, 
fig. 1. 
1857. — noposa, Pictet and Renevier. Ibid., p. 94, pl. xii, fig. 2. 
1865. — —  H. Coquand. Mon. Aptien de l Espagne, p. 133. 
1866. = — F. J. Pictet and G. Campiche. Foss. Terr. Crét. Ste. 
Croix (Matér. Pal. Suisse, ser. 4), p. 385. 
1875. — —  Lycett, p. 106, pl. xxv, figs. 1, 2; pl. xxxvii, figs. 5, 6. 
1875. — — var. Orpienyana, Lycett. Ibid., p. 107, pl. xxiv, figs. 
1—3. 
1896. — — A. Wollemann. Zeitschr. d. deutsch. geol. Gesellsch., 
vol. xlviii, p. 846, 
1900. _ — — Die Biv. u. Gastrop. d. deutsch. u. hol- 
lind. Neoc. (Abhandl. d. k. preus- 
sisch. geol. Land., N. F., pt. 81), 
p- 90, pl. iv, fig. 8. 
Non 1852. — — F.J. Pictet and W. Roux. Moll. Foss. Grés verts de 
Gentve, p. 454, pl. xxxv, fig. 5. 
Remarks.——There appears to be a perfect passage from the typical 7’. nodosa to 
the variety named by Lycett Orbignyana. 
Lycett regarded 1’ cineta, Agassiz, as a synonym of 7’. nodosa; I have seen no 
examples of the former, but its area appears to be proportionately larger, while the 
ribs seem to be more nearly perpendicular to the carina and more nearly parallel 
to the ventral margin than in the English specimens. 
Types.—I have not found the type; it came from the Hythe Beds of Hythe. 
The specimens figured by Lycett are in the Museum of Practical Geology. 
Distribution.—Hythe Beds of Hythe and Lympne. Crackers of Atherfield. 
Perna-bed of Atherfield and Redcliff. Folkestone Beds near Copt Point, Folke- 
stone. Claxby Ironstone of Tealby (fide Lycett). 
TRIGONIA TEALBYENSIS, Lycett, 1875. 
1875. Lycett, p. 114, pl. xxviii, fig. 7. 
Type.—In the Woodwardian Museum, Cambridge. 
Distribution.—Spilsby Sandstone (zone of Bel. lateralis) of Claxby. 
