Original Description of Rostellaria (Rimella) knappiana by Maury, 1912, p. 89:
- "Shell of moderate size, slender, subfusiform, with a high, very acute and tapering spire; whorls nine or ten; spiral sculpture, on very well preserved specimens, of microscopic striae which are exceedingly fine all over the shell, and of about ten strong spiral lines at the base; longitudinal sculpture of sharp-edged, close-set plications which are present on all the whorls (although in some cases the whorls appear perfectly smooth, which is beause the enire outer surface has been removed by erosion); this handsome and even plication of the whorls, extending over the last volution as well, immediately differentiates this species from R. fowleriana; characters of base of shell and outer lip shown by the second figure; the posterior canal in adult shells forms a sharply-ridged gutter extending almost to the tip of the spire to which it is adherent."
Locus typicus: "Bed No. 8", Soldado Rock, Gulf of Paria, Republic of Trinidad and Tobago
Stratum typicum: Lignitic Eocene.
Dimensions: "Height of shell 22, greatest width 8 mm."
Remarks.-This shell is one of the most abundant species in the Soldado Lignitic fauna."
Etymology: "The writer takes great pleasure in naming it in honor of Mr. I. N. Knapp, of Morgan City, Louisiana, whose kind gift of deep well fossils has done so much to further our knowledge of the depth and extent of the Quatenary strata of the Gulf States."
Rostellaria (Rimella) knappiana Maury, 1912, pl. XII, fig. 12, 13