Amphistegina gibbosa d’Orbigny, 1839b

Figure 7.3-4

1839b Amphistegina gibbosa d’Orbigny, p. 120, pl. 8, figs. 1-3.

2014 Amphistegina gibbosa d’Orbigny; Panchang and Nigam, pl. 32, fig. 11a-c.

Description. Test lenticular, strongly biconvex in the central portion, flattened at the sides, wall calcareous, surface smooth; chambers radial initially, later curved towards the periphery, chamber arrangement low trochospiral, coiling involute; peripheral margin subacute, sutures slightly depressed; aperture interiomarginal, a narrow slit, bordered by a lip.