Shell elongate-fusiform, thin, pale waxen or brownish, glossy; nucleus blunt, globose, of about one whorl; other whorls seven or more, little rounded, the second, third, and fourth showing 8-10 sharp high transverse ribs, a little shouldered behind, and crossed by fine spiral threads and grooves most distinct on the posterior side of the whorl; one of the threads is stronger than the others and angulates the ribs in crossing them; the sculpture becomes obsolete or nearly so on succeeding whorls, the fine distant grooves persisting longest; specimens differ in this respect; usually the succeeding whorls are smooth except for incremental lines, appressed toward the suture and with a little fine spiral grooving on the canal; aperture elongated, acute behind; outer lip smooth, thin, and sharp; canal about half as wide and nearly as long as the aperture, slightly recurved; columella without callus, somewhat flexuous ; at its middle are three plaits, the largest being posterior, very thin, elevated, and somewhat oblique. Lon. of shell, 15.5 mm; of aperture, 9.0 mm; max. lat. of shell, 5.0 mm.
DESCRIBED BY DALL as Mesorhytis meekiana

This specimen conforms in all essential details with Dalls original material, consisting of dead but fresh specimens from three localities; the figured specimen is 15.5 mm long and 5.0 mm broad. The present specimen is 26.0 mm long and 8.2 mm broad, therefore possibly mature. The apex is lost and there are six remaining postnuclear whorls. Strong axial ribs are present on the second, third, and fourth whorls, becoming obsolete on the fifth. These whorls also show fine, spiral threads most distinct on the upper half, one of which is stronger than the rest. All fade away in the fifth whorl. The body whorl is somewhat more inflated than in Ball's illustrated specimen, the outer lip slightly flared and the anterior canal more distinctly recurved, features probably associated with maturity. The parietal wall has an extremely thin, inconspicuous glaze but is not callused. The columella is moderately flexuous, with three high, narrow, oblique plaits of which the posterior (upper) one is strongest. The operculum is translucent corneous yellow, small, thin, and delicate. It is spatulate in shape, weakly curved, with nearly parallel sides. The nucleus is terminal, the apex truncated, perhaps because of wear; the muscle scar, at the opposite end, is almost circular. The radula is triserial. The rachidian has three strong cusps on a bent basal plate. The laterals have a single flattened, curved, clawlike cusp arising terminally from an elongated base.

Type locality.—Off Morro Light, Cuba in 450-730 m.
Range.—Deep waters (440-1100 m) of the Gulf of Mexico, Cuba, Jamaica, and the Bahamas.
Discussion.—This shell has had quite a number of names since Dall originally referred to it as Mesorhytis, a genus erected by Meek (1876) to include some Cretaceous fossils. The genus was originally placed under the subfamily Fasciolariinae. Bayer (1971) placed the shell in the Turbinellidae based on shell morphology and anatomy and moved the species to the genus Teremachia Kuroda, 1931. Because the genus Teremachia is restricted to the southwestern Pacific, the species was later referred back to the genus Mesorhytis until Kantor et al. (2001) synonymized the genus Mesorhytis with the genus Exilia, placing the shell in its current taxonomic position.
This species was described by Dall (1889a) from only a "couple" of dead specimens collected aboard the R/V Blake in the late nineteenth century. Bayer (1971) collected one live aboard the R/V Gerda off the southwestern coast of Jamaica in 1970 and some specimens have since been dredged alive from shallower water (30-60 m) off Miami and the Florida Keys by Kevin and Linda Sunderland of Fort Lauderdale, Florida (pers. comm.). Two additional specimens were dredged aboard the R/V Bellows in 2002 off Victory Cay, Bahamas. This is the first known record of Latiromitra meekiana from the Bahamas. Attesting to the rarity of this species, Dr. Bayer noted that, over a period of more than six years of trawling and collecting in the tropical western Atlantic during the Deep-Sea Biology Program of the Rosenstiel School of Marine and Atmospheric Sciences, among many specimens of gastropods, only two specimens of this species were ever collected.
The specimens collected aboard the R/V Bellows are only approximately half the length of full-sized specimens, and they are fairly thin and delicate and pure white in color. On the unbroken specimen, there is a blunt and globose protoconch that persists for only one whorl. There are six postnuclear whorls that are rounded and have about 10 raised axial ribs on the second, third, and fourth whorls that abruptly become obsolete on the fifth whorl. There, the sculpture becomes dominated by 5-6 fine, spiral threads that are restricted to the posterior part of each whorl. None of the spiral threads appear to be stronger than the rest, as they are all nearly equal in thickness and are fairly faint mainly visible under magnification. The outer lip is smooth and sharp and the parietal wall is finely glazed, but there is no visible callus. The columella has three distinct, narrow, oblique plaits which rise at nearly right angles from the columella. The broken specimen differs from the complete specimen in being larger (reconstructed altitude of protoconch 15.5 mm), having a more inflated body whorl, and a much more developed spiral sculpture, composed of 10 raised ribs on the penultimate whorl and over 30 raised ribs on the body whorl. There are 14 raised axial ribs on the penultimate whorl that appear just below the suture on the body axial sculpture of the shell becomes obsolete is variable from specimen to specimen, which is apparent when both Bahamas specimens are compared. The degree of spiral sculpture is also a variable character, as can be seen in the two specimens from the Bahamas. Bayer (1971) also observed that as the shells mature, the body whorls become slightly more inflated, the outer lips become more flared, and the anterior canals are more distinctly recurved.
Latiromitra meekiana most closely resembles L. chaunax (Bayer, 1971) from west of St. Lucia, Lesser Antilles but differs in lacking axial ribs on the body whorl, in having 5-6 subsutural spiral cords rather than one, and in having larger, more distinct columellar plaits. Another species, L. costatus (formerly Mesorhytis costatus) Dall, 1890, was dredged from 687 fathoms off St. Kitts, Lesser Antilles. This species is distinctly different from both L. meekiana and L. chaunax, primarily in having a more developed sculpture of numerous spiral threads and raised axial costae covering the entire shell.

The larger of two syntypes of M. meekiana Dall (USNM No. 86970), when compared with the type of Latiromitra barthelowi Bartsch (from ALBATROSS Sta. 5425 in the Sulu Sea off Cagayan I., 495 fm = 905 meters, USNM No. 238444), is smaller and not so strongly sculptured, and its columellar plications are higher and thinner. The axial sculpture of L. barthelowi is conspicuous and consists of sharply defined axial ribs separated by narrower deep channels. This sculpture fades out rather abruptly on the penultimate whorl, consequently the body whorl is smooth except for irregular growth marks. The three columellar plications are low but distinct, originating rather deep within the aperture so they are not conspicuous in direct apertural view. Perhaps it is this fact that caused Weaver & du Pont (1970: 177) to state that plications are absent, although they are visible in the photograph reproduced on their plate 75D.