106 HIND : NEW CARBONIFEROUS NAUTILOIDS. 
Wildi, but this shell has a different habit altogether, increasing 
rapidly in its transverse diameter and being much more expanded 
from side to side than the species under discussion. 
GLYPmOCERAS VESICULIFER, DE KONINCK, SP. 1880. 
(Plate VI., figs. 2, 2a, 2b.) 
Goniatites vesiculifer, De Koninck, 1880, Faune du Calcaire 
Carbonifere de la Belgique, p. 109, PI. xlix., figs. 10, 11. 
Specific characters. — Shell small, involute, comparatively- 
broad for its height. Umbilicus small and steep, margin very 
gentl}^ bevelled at the expense of the edge. The periphery is 
broad, gently convex, separated on each side from an inflated 
margin by a longitudinal sulcus. Below the roUed margin the 
side of the whorl is flattened and depressed. 
The suture line is drawn from the specimen. 
Ornamentation. — The sides of the sheU are adorned by a 
number of smaU, slightly elevated curved radiating costae, which 
pass from the edge of the umbilicus and become lost on the swollen 
band. Between the ribs the lateral surface is covered with 
numerous regular longitudinal lines. The surface of the inflated 
margin is finely punctate. Test thin. 
Dimensions. — The shell, which is incomplete, and lacks 
entirely the body chamber, measures : — 
From side to side at the inflated margin, 13 mm. 
Greatest vertical diameter, 21 mm. 
Localities. — The Carboniferous Limestone of Elbolton, near 
Cracoe, Yorkshire (Upper Dibunoplyllum zone). De Koninck 
states that he found this species at Settle (op. supra, cit.). 
Observations. — The peculiar swoUen peripheral margins and 
the flattened depressed sides of this shell at once distinguish the 
species from all other described forms. De Koninck bases his 
description on specimens from the Carboniferous Limestone of 
Vise, but his specimens did not show the ornamentation of the 
shell and the weU-marked curved costae on the flat lateral surface. 
He described the swollen peripheral margin as being formed of 
small vesicles, and it seems apparent that such was the case, for 
these bands do not appear on that part of my specimen, which 
