44 MOLLUSCA FROM THE CRAG. 



Shells with an elongated canal, which properly constitute the genus Fusus, are 

 characteristic of a tropical climate. The greater part of the species of this genus 

 from the Crag are northern forms. 



1. Tuophon antiquum. Mutt. Tab. V, fig. 1, a — k. 



Tkitonium antiquum. Mull. Zool. Dan. tab. 118, fig. 1-3, 1773. 

 Murex contrarius. Gmel. Syst. p. 3564, 1788. 

 Fusus antiquus. Ency. Meth. pi. 426, fig. 5. 



— despectus (?). - pi. 426, fig. 4. 



— contrarius - pi. 437, fig. \, a 6. 

 Murex despectus. Mont. Test. Brit, p. 256, 1803. 



— antiquus (?). - - - p. 257. 



— stkiatus. J. Sow. Min. Conch, t. 119, 1815. 



— var. carinatus - - - t. 22, 1813. 



— contrarius. t. 23. 

 Buccinum contrarium. G. Sow. Genera, fig. 4. 



Fusus contrarius. Phil. En. Moll. Sic. vol. ii, p. 179, 1844. 



— — Nyst. Coq. foss. de Belg., p. 500, pi. 41, fig. 1. 



— antiquus. Lam. An. sans Vert. (2d edit.) ix, p. 477, 1845. 



— carinatus p. 449. 



CONTRARIUS p. 462. 



SINISTRORSUS (?). p. 374. 



Tritonium antiquum. Loven. Ind. Moll. Scand. p. 11, 1846. 



Bale. Hist, of Harwich, pi. 10, fig. 5-6, 1730. 



Tr. Testa crassd, turritd, fusiformi, sulcata, carinatd, vel tenuissime striata ,- apice 

 papilliformi, anfractibus valcle convexis, tumidls ; aperturd ovatd ; labro simplici, hit us 

 lavigato ; canali brevi, emarginatd. 



Shell variable, strong, thick, ponderous, fusiform, turreted, sulcated, bicarinated, 

 or finely striated, with a white, naked, and mammillated apex ; whorls, convex, 

 tumid ; aperture ovate ; lip simple, smooth within ; canal short. 



Axis, 6 inches. 



Locality. Red Crag, passim. 



Mam. Crag, Bramerton and Bridlington. Recent, Britain. 



I have very little doubt of the shell found so abundantly in the Red Crag, with 

 its sinistral volutions, being a variety of the common Tr. antiquum. This species is 

 exceedingly variable, and no dependence can be placed upon any proportional 

 dimensions of its aperture, as may be seen from the extremes of variation figured in 

 Tab. v, and between which every intermediate form may be procured. Some speci- 

 mens have an aperture exceeding two thirds of the axis, while in others it is not 

 more than one third. The smooth and obtuse state of the young shell, at the apex 

 of perfect specimens, is a good distinguishing character in this species ; but in the 

 greater number of the fossil specimens that part is destroyed, excepting in the 

 striated variety, so common at Walton-on-the-Naze. The Belgian shell, figured by 

 M. Nyst, is an extreme variety of this species. I have never seen the canal so 



