I 



NEW FLORIDA MOLLUSKS — BARTSCH AND REHDER 131 



Aperture elongate-ovate, decidedly channeled anteriorly and with a 

 shallow sinus at the posterior angle ; outer lip acute ; inner lip re- 

 flected over the columella as a callus, extending on the parietal wall. 

 Type: Rubellatoma nibella (Kurtz and Stimpson) {=Mangelia ru- 

 heJJa Kurtz and Stimpson). 



RUBELLATOMA DIOMEDEA, new species 

 Plate 17, Figure 3 



Shell elongate-turreted. Nuclear whorls bright chestnut-brown, 

 the rest of the whorls with a broad brown band covering the posterior 

 half of the whorls. There is a second broad band a little less wide 

 immediately anterior to the periphery followed by a pr^le zone of al- 

 most equal width, while the tip is chestnut-brown. The interior of 

 the aperture shows the exterior coloration. The first 1.5 nuclear 

 whorls are smooth, the succeeding half turn is marked by slender, re- 

 tractively curved, axial riblets followed by the postnuclear sculpture. 

 Postnuclear whorls appressed at the summit, with a decided angle, the 

 crest of which occupies the anterior fourth between the summit and 

 suture. The whorls are marked by strong sinuous axial ribs, which 

 attain their highest elevation at the angulation and taper gently 

 toward the summit and columella where they evanesce. Of these 

 ribs, 12 occur on the first postnuclear turn, 9 on the second, third, 

 and fourth, 10 on the fifth, and 7 on the last seven-tenths of a turn. 

 The axial ribs are not quite so wide as the spaces that separate them. 

 The entire surface of the shell is marked by numerous incremental 

 lines and equally strong spiral striations, the combination of which 

 gives to the surface a feebly fenestrated pattern. Base rather long, 

 marked by the same sculpture as that which characterizes the spire. 

 Columella short, stubby, marked by incremental lines and weak 

 spiral threads. Aperture elongate-ovate, decidedly channeled an- 

 teriorly, with the posterior sinus shallow immediately below the 

 summit. Outer lip somewhat thickened behind the edge, sharp at 

 the edge, slightly protracted anteriorly at the notch and marked like 

 the s})ire; the inner lip is appressed to the columella as a callus ex- 

 tending up on the parietal wall. 



The type, U.S.N.M. No. 508645, was collected by Dr. Perry at 

 Sanibel Island, Fla. It has 7.6 whorls and measures : Length, 9.7 

 mm.; greater diameter, 4.0 mm. An additional specimen is in Dr. 

 Perry's collection. 



Three young specimens, U.S.N.M. No. 323723, were collected by the 

 U. S. Bureau of Fisheries steamer Albatross at station 2389 in 27 

 fathoms, on gray sand and shell bottom off Mobile Bay, Ala. 



This species differs from RnheUatonm ruheXla (Kurtz and 

 Stimpson) in having the nuclear whorls chestnut-brown instead of 



