Conus medialira (Vokes, 1938)

DESCRIPTON.

Shell of medium size, spire moderately high, concave in contour, shoulder truncate; nucleus smooth, rounded, erect, of two and one-half whorls; first two post-nuclear whorls tuberculate, the tubercles well developed at the nucleus and becoming progressively weaker; the subsequent volutions, eight to nine in number, excavated, marked only by growth lines; aperture broader anteriorly, outer lip moderately retractive, anal notch deep, siphonal notch weak, siphonal fasciole hardly discernible; lower part of body whorl marked by slightly irregular rounded spiral grooves separating flat-topped riblike spaces of approximately twice the width of the grooves, each with a median secondary groove.

HOLOTYPE.

NO. 25000; length 51,2 mm.; diameter 29,5 mm.

Conus (Leptoconus) stenostomus (Sowerby, 1850), Santo Domingo, has a somewhat similar sculpture pattern on the body whorl, but differs markedly in its strongly retractive outer lip and in the shape and sculpturing of the spire whorls ⁽¹⁾.

Conus stenostomus (Sowerby I, 1850)

Shell of medium size, with sharply angulated shoulder, narrow aperture, and deep U-shaped posterior sinus which, as the shell grows, renders the upper surface of the whorls on the spine concavely sulcate. Our largest Trinidad specimen is 52 mm, in height and 28 in width⁽³⁾.

Sowerby's type was collected by Colonel Heneken in Santo Domingo where we obtained this species in the Gurabo formation. It is also found at Bowden, Jamaica, and in the Gatun stage of Port Limon, Costa Rica⁽³⁾.

Locality. — Springvale (Trinidad).

Horizon. — Upper Miocene.