CYRTINA. 113 
3. CYRTINA HETEROOCLITA, var. Demartit, Bouchard, MS. Pl. XII, fig. 10. 
1864. Cyrtina Demaruit, Davidson. Brit. Foss. Brach., vol. iii, pt. 6, p. 50, 
pl. ix, figs. 15B—17. 
1885. —_ — Maurer. Abhandl. Grossh. Hessisch. Geol. Landes., 
vol. i, pt. 2, p. 164, pl. vil, figs. 5—6 ¢. 
1886. — HETEROCLITA, var. Demarui, @hlert. Ann. Sci. Géol., vol. xix, 
p- 42, pl. iui, figs. 35—41. 
Remarks.—Davidson seems to have established this species chiefly on specimens 
from Fergues, where he describes it as common. He only mentions two or three 
Devonshire specimens ; and says that it is chiefly distinguished from C. heteroclita 
by the longitudinal groove in the centre of the mesial fold. 
In my own Collection are two specimens having a distinct biplicated mesial 
fold, while in about a dozen there is a similar linear groove on the summit of the 
fold, but generally so slight as to be discernible only undera lens. Ina clear 
specimen of C. heteroclita, on the other hand, I find that the mesial fold, which is 
simple on the upper part, becomes suddenly deeply trifid near the margin. 
From the evidence, therefore, of the English specimens I should have little 
hesitation in following @hlert and uniting the present species with C. heteroclita. 
Sp. subconica, Phillips (not Sowerby), which Davidson gives as a synonym of 
the present form, is said only to differ from C. heteroclita by the narrowness of 
the mesial fold; and that hardly seems a distinctive feature, judging from the great 
variability of the latter shell. 
4, Cyrtina amBLycona, Phillips, sp. 
1841. TEREBRATULA aMBLYGONA, Phillips. Pal. Foss., p. 88, pl. xxxv, fig. 169. 
1864. Cyrrmna amBityGona, Davidson. Brit. Foss. Brach., vol. iii, pt. 6, p. 51, 
vol. ix, figs. 18—20. 
Remarks.—This species is evidently very rare at Lummaton, as I have never 
succeeded in finding a specimen of it there. 
There is a single specimen in the Torquay Museum from Lummaton (?), which 
differs from Davidson’s figures in the absence of a fold and the greater irregularity 
of the ribs. 
The original specimen figured both by Phillips and Davidson from Barton is 
in the British Museum. 
VOL. If. 15 
