﻿206 DEVONIAN FAUNA. 



sunk below the highest plane of the shell. Apex minute, incurved, and direct, 

 facing neither upwards nor downwards. Body-whorl very elongate, perpendi- 

 cularly compressed, and very slowly increasing; in section, broadly oval, most 

 convex round the back which sometimes is almost bluntly angular, less convex 

 above and below ; longitudinally convex along the back with a decreasing 

 curvature towards the mouth, definitely concave along the inner side, sometimes 

 showing indistinct longitudinal grooves. Mouth small. Peristome slightly 

 sinuous, not expanded. Surface ornamented with irregular undulating growth- 

 lines and numerous microscopical striae, crossed sometimes, especially in the lower 

 parts, by occasional fine ridges, in which case the striae become deeply sinuous 

 between them. 



Size. — A specimen in Mr Vicary's Collection measures — width 16 mm., depth 

 18 mm., height 12 mm. A specimen in the Woodwardian Museum measures 

 — width 15 mm., depth 12 mm., height 9 mm. 



Localities. — From Lummaton there are eight specimens in my Collection and 

 four in the Woodwardian Museum. From Barton there are three specimens in 

 the British Museum, two of which have the lower lip more than usually expanded. 

 From Wolborough there is a specimen in Mr. Vicary's Collection. 



Remarks. — This little species seems very well defined, and very different from 

 any of the accompanying forms. It is notable for the very slow rate of increase 

 of its whorl, by the great distance of its apex from the plane of the mouth, and 

 for its great horizontal symmetry. If it be stood on its mouth the perpendicular 

 from the apex falls some distance outside the centre of the inner margin of the 

 aperture. 



The shell described by Maurer appears identical with the English form, as far 

 as can be judged from the defective cast which he figures. This shell he submitted 

 to Barrande, who described it as " rapproche de Gapulus restrains, Barr., e 2 — /V 



There is the usual amount of variability between individual specimens of this 

 species of Gapulus, both in the length and curvature of the shell and in other 

 points, but at the same time there is a general similarity which marks them as all 

 belonging to the same species. Perhaps the most aberrant specimen is one in my 

 Collection which is very long and flat and almost rhomboidal in section, being 

 flattened on the back, lateral, and inner sides, and angulated at the corners. 



Affinities. — Orthonychia subrectum, Hall, 1 is slighter and less recurved. 



Platyceras Thetis, Hall, 2 has a longer, freer, and more recurved apex. 



One of Kayser's 3 figures of Capulus Zinckenii, F. A. Romer,* sp., is something 



1 1859, Hall, ' Twelfth Eep. N. T. State Cab. Nat. Hist.,' p. 18. 



2 1879, Hall, ' Pal. N. T.,' p. 8, pi. iii, figs. 11—16. 



3 1878, Kajser, 'Abhandl. Geol. Specialk. Preuss.,' Band ii, pt. 4, p. 39, pi. xv, figs. 5 — 7. 



4 1843, P. A. Eomer, 'Harz.,' p. 27, pi. vii, figs. 4« — c. 



