﻿116 BRITISH FOSSIL TRIGONIiE. 



Trigonia aliformis, Furk. Plate XXV, figs. 3, 3 a, 4, 4(2, 5, G. 



Tkigonia aliformis, Parkinson. Org. Remains, vol. iii, p. l/C, tab. xii, fig. 9, 1811. 



— aLjEFORMIS, Sowerby. Mineral Conchology, vol. iii, tab. 215, 1818. 



— ALIFORMIS, Beshayes. Coq. car., p. 33, tab. x, figs. 6, 7, 1831. 

 Lyriodon ALiEFORME, Bronn. Leth. Geog., vol. ii, p. 700, tab. xxxii, fig. 15, 1837-8. 

 Teigonia aliformis, Piisch. Polens Palaontologie, p. 60, 1837. 



— aliformis, Fitton. Quart. Journ. Geol. Soc, vol. iii, p. 289 (pars), 1843. 

 ■■ — — Agassiz. Trigonies, p. 31, tab. vii, figs. 14 — Ifi, tab. viii, fig. 1 2, 



1840. 



— ALiEFORMis, Morris. Catalogue, 2nd ed., p. 228 (pars), 1854 ; exclude 



L. G. S. of Sandgate and Boughton. 



— aliformis, Pzc^e^ Paleont. Suisse, torn, i, pi. xiv, fig. 1, 1857; exclude 



fig. 2. 



Exclude the following figures of Trigonice named T. aliformis : 



Leopold de Buch, Petrefacta recuillies en Araerique, par A. de Humboldt et par Ch. 



Degenhardt, fig. 10, 1839. 

 Forbes, Geol. Trans., 2 ser., vol. vii, part iii, p. 151, 1846. 

 D'Orbigny, Pal. Fran., Terr. Cret., vol. iii, p. 14;^, pi. 291, figs. 1—3. 

 Lyroden aliforme, Goldfuss, Petref., vol. ii, tab. 137, fig. C, 1836. 

 Pictet and Roux, Grfes Vert, pi. xxxv, figs. 2 a, b, 1847-53. 

 Pictet and Renevier, Terr. Aptien de la Perte du Rhone, pi. xiv, fig. 2, 1857. (Fig. 1 



is from a Blaekdown specimen.) 



Triyoyiia aliformis is placed at the head of the first group ; it is characterised as 

 follows : 



Shell sublunate, inflated anteally, produced, attenuated and depressed posteally; 

 urabones much elevated, antero-mesial, pointed, much recurved and incurved ; anterior 

 side produced, its border rounded ; lower border rounded, but somewhat excavated 

 posteally; hinge-border lengthened, concave, terminating posteally in a rostrated and 

 attenuated extremity ; ligamental aperture narrow, inter-umbonal. Escutcheon 

 lengthened, deeply concave, occupying the entire upper surface of the shell ; its superior 

 or inner border is plain and much raised; its outer border is formed by a narrow, 

 elevated, and rounded area ; it is traversed transversely or obliquely by numerous closely 

 arranged, small, serrated costellae, which are prominent near to the umbones, but become 

 only faintly traced posteally. The area is very narrow, raised, and convex ; it is 

 rendered bipartite throughout its entire length by a deep groove and its superior or 

 umbonal portion has a few small, ridge-like, transverse costellae ; the remainder of its 

 length has small, irregular, transverse plications. 



The other portion of the surface has a numerous series of costa?, which originate at 



