﻿234 DEVONIAN FAUNA. 



as it has the same tendency to the upward elongation of the spire, and is a larger 

 specimen, it seems most probable that these differences are to be explained by age. 

 The ornamentation in the English shell is too obscure to be compared with that 

 of the German shell with certainty, but it seems to be much in the same nature, 

 except that the latter shows no signs of median angulation. 



Affinities. — Turritella cancellata, Groldfuss, 1 has similar, but twice as fine, orna- 

 mentation. It seems very nearly to correspond in general shape, but Goldfuss's 

 figure gives no points for generic comparison. 



Achrisina multicristata, CEhlert, 2 differs in having narrower whorls, and in 

 being only ornamented with definite, and probably more numerous, spiral lines, 

 whereas there is little doubt that the English shell was more or less tuberculous. 

 Though the base of the French shell is gone, it is sufficiently like the English 

 shell in general form to show that it very probably may belong to the same 

 genus. 



3. Genus. — Antithoohus, gen. nov. 



Shell spiral, turbiniform, sinistral, of few loosely coiled and almost wholly 

 exposed, convex whorls. Sutures large, wide, and deep. Mouth subcircular or 

 subquadrate. Peristome continuous. Umbilicus minute. Ornamentation con- 

 sisting of both spiral and longitudinal threads. 



In this genus I would place the shell described below, and also Scalaria 

 antiqua, Minister. I have been unable to find any known genus to which these 

 shells might be satisfactorily referred, nor have several paleontologists whom I 

 have consulted on the question been able to recognise their generic position. 

 They appear to bear so strong a general likeness to many of the Scalaridas that I 

 have no hesitation in referring them to that family ; but to the genus Scalaria 

 they clearly, in the opinion of Mr. Etheridge, F.R.S., and others, do not belong. 

 They approach the genus Scoliostoma, but from that they are separated by the 

 absence of any irregularity in the body- whorl, and other points. 



In both the above-named species the shells are sinistral, but it may be unsafe to 

 regard this as a generic quality until a larger number of species are known, as 

 others may be found which agree in every other quality, but have dextral shells. 



1 1844, Goldfuss, ' Petref. Germ.,' vol. iii, p. 103, pi. cxevi, figs. 10 a, b. 



2 1887, CEhlert, 'Bull. Soc. d'Etud. Sci. d' Angers/ p. 10, pi. viii, figs. 4, ia. 



