﻿BYSSIFER^E. 



179 



§ VIII. — Byssifer^. 

 Trigonia carinata, Ag. Plate XXXV, figs. 3, 4, 4 a, 5, ha, 6, 6a. 



Trigonia carinata, Agassiz. Trigonies, p. 45, tab. vii, fig. 7, 10, 1840. 



— sulcata, Agassiz. Trigonies, p. 44, tab. xi, fig. 16; tab. viii, figs. 5, 11 



(Moulds). 



— harp a, Beshayes. Leymerie, Mem. de la Soc. Geol. Fran., torn, v, pi. ix, 



fig. 7, 1842. 



— carinata, Forbes. Quart. Journ. Geol. Soc, torn, i, p. 244, 1845. 



— — oVOrbigny. Pal. Fran. Terr. Cret., vol. iii, p. 132, pi. 286, 



1843. 



— harpa, Matheron. Catal. de Corps, org. foss. du Depart des bouches du 



Rhone, p. 166, 1842. 



— carinata, Marcou. Rech. Geol. sur l'Jura Salin., p. 142, 1846. 



— sulcata, Marcou. Idem. 



— carinata, Fitton. Quart. Journ. Geol. Soc, vol. iii, p. 289, 1847. 



— — cCOrbigny. Prodrome de Paleont., vol. ii, p. 78 (pars) ; exclude 



T. elongata, 17 etage, 1850. 



— harpa, Archiac. Hist. Progr., torn, iv, p. 322, 1851. 



— carinata, Corneul. Bull. Soc. Geol. de Fr., torn, viii, p. 435, 1851. 



— — Bavignier. Statist. Geol. de la Meuse, p. 473, 1852. 



— — Studer. Geol. Schweiz., torn, ii, p. 281, 1853. 



— — Morris. Catalogue, p. 228, 1854. 



— — Cotteau. Moll. foss. de l'Yonne, p. 76, 1854. 



— — et sulcata, Trilobet. Bull. Soc. Natr. Neuchatel, torn, iv, 



p. 73, 1856. 



— — Pictet et Renevier. Paleont Suisse, Terr. Aptien, p. 101, 1857. 



— — ■ Archiac. Bull. Soc. Geol. de Fr., torn, vi, p. 496, 1857. 



— — Lycett. On a Byssiferous Fossil Trigonia, Ann. and Mag. Nat. 



Hist., p. 17, 1870. 



Shell ovately elongated, or somewhat spindle shaped in young forms ; very convex in 

 the adult state, umbones prominent, sub-terminal, acute, much arched inwards, and 

 slightly recurved. Anterior side very short, truncated, inflated, its border forming with 

 the other valve a large depressed space ; the posterior border is somewhat convex, 

 curved gradually towards the lower extremity of the prominent marginal carina. Escut- 

 cheon of great breadth and length, slightly concave, its borders raised in every direction, 

 traversed by strong diverging rugose scabious ridges. Area very wide, conspicuously 



Cotteswold districts it is remarkable that of the seven species of Trigonia obtained in the Cotteswolds above 

 enumerated, two only, T. pullus and T. Phillipsii, occur in South Lincolnshire, and even these have 

 disappeared in the limestone at Appleby. 



