Description

“Zeminolia meridiana n.sp. (Figs. 1. 2).

 

Shell small, turbinate, smooth and shiny, deeply umilicate [sic]. Whorls 5 including a smooth bulbous protoconch of 1½ whorls, terminated by a small varix. Spire less than height of aperture, suture abutting. To the naked eye the whole shell appears smooth and polished, but under moderate magnifications the first and second post-nuclear whorls are seen to be sculptured with 6-7 fine raised spiral threads. These gradu­ally disappear across the penultimate whorl. All whorls with well marked growth lines, most prominent near the suture, especially marked on the body whorl. The umbilicus is narrow for the genus, but deep, bordered by a smooth spiral ridge. Aperture subcircular, discontinuous. Outer lip thin, parietal wall with very thin glaze; columellar wall slightly thickened, almost perpendicular, reflexed at junction of circum-umbilical ridge. Colour, whitish, with a faintly green iridescent sheen. Oper­culum horny, circular, nucleus central, spiral of 5 whorls.

 

 

Height, 4.5 mm.; major diameter, 5.5 mm.; diameter of umbilicus, 1.4 mm.

 

 

Holotype (M.5666) and paratype (M.5667) in Dominion Museum.

 

 

This species seems best placed in Zeminolia. The protoconch agrees well with that of the genotype, though the umbilicus is narrower than usually found in this genus. The degeneration of sculpture is foreshadowed in Z. lutea Powell. For comparative purposes, outline drawings are given of the protoconchs of Zeminolia plicatula Murd. and Suter, Z. meridiana n.sp. and Antisolarium egenum (Gould). (Text Fig. 2).”

 

 

(Dell, 1953: 42-43)