GASTROPODS: TROCHIDAE TO TURRITELLIDAE


whorls. The umbilicus of immature shells is not completely filled with callus (pl. 17, fig. 41).
 T. andrium is closely related to T. caroniense Maury i1925, p. 249, pl. 43, figs. 3, 4), a late Miocene species from Trinidad, but has a flatter columellar lip and flatter rmbilical callus. The recent Ecuadorean T. millepunctatum Pilsbry and Olsson (1945-52, p. 253, pl. 23, figs. 1, la, 1b, 1945) has more coarsely punctate spirals, and is smaller and thinner. The Recent western Panamic T. imperfectum Pilsbry and Olsson (194552, p. 254, pl. 22, figs. 2, 2a, 2b, 1945) also is smaller and thinner, and has a thin, narrow umbilical callus.
 Occurrence: Lower and middle parts of Gatun foriation (middle Miocene). Lower part, locality 137. Middle part, eastern area, locality 147i.
 Subgenus Pseudorotella Fischer
Fischer, Jour. Conihyliologie, t. 6, p. 52, 1857.
Type (monotype): Pseudorotella semistriata (d'Orbigny) (Rotella
 semistriata d'Orbigny), Recent, Cuba.
 Pseudorotella is used in the present report for small, smooth or spirally sculptured teinostomes that have a moderately thick shell, exposed relatively high spire, wide umbihical callus filling-or not quite filling-the
-umbilicus, and narrow parietal callus. This usage may be found to be inappropriate when specimens of the type species are available. The type species has fine spiral striae above the periphery, according to dOrbigny's illustrations.
 As suggested by Pilsbry and McGinty (1945-50, pt. 1, p. 2, 1945), subgeneric rank is preferable to the generic rank that has been assigned to Pseudorotella (Woodring, 1928, p. 445). The Miocene Jamaican "Pseudorotella'' homala Woodring (1928, p. 447, pl. 38, figs. 13-15) represents a minor group of teinostomes, more closely related to Aepystoma than to Pseudorotella, characterized by a bicarinate truncated periphery and relatively strong spiral sculpture.
 Teinostoma (Pseudorotella) pycnum (Woodring)
 Plate 17, figures 25-27
Pseudorotella pycna Woodring, Carnegie Inst. Washington Pub.
 385, p. 446, pl. 38, figs. 10-12, 1928 (Miocene, Jamaica).
 Small, moderately thick-slielled, periphery rounded. Body whorl pinched against suture, producing a suggestion of a sutural collar, corresponding to faint gutter between outer lip and parietal callus. Umbilical callus thick, filling umbilicus. Parietal callus narrow, its edge sharply defined.
 Height 0.8 mm, diameter 1.3 mm (figured specimen).
 Type: USNM 135502.
 Type locality: Bowden, Jamaica, Bowden formation (middle Miocene).


 The faint sutural collar and narrow parietal callus are characteristic features of Teinostoma pycenum. The few specimens from the Gatun formation are slightly smaller than the type. T. vitreum (Gabb) (Pilsbry, 1922, p. 399, pl. 37, figs. 3, 3a, 3b), from the Cercado formation of the Dominican Republic, lacks the faint sutural collar. T. parvicallum Pilsbry and McGinty (1945-50, pt. 1, p. 4, pl. 2, fig. 2, 1945), a Recent teinostome from Florida, is slightly larger and has a higher spire.
 Occurrence: Lower and middle parts of Gatun formation (middle Miocene). Lower part, locality 138. Middle part, eastern area, locality 147b. Bowden formation (middle Miocene), Jamaica.
 Teinostoma (Pseudorotella) stemonium Woodring, n. sp.
 Plate 17, figures 1-3
 Small, moderately thick-slielled, periphery rounded, but marked by a spiral thread. Body whorl somewhat pinched against suture. Whorls smooth between suture and periphery. Periphery and base near periphery sculptured with four or five relatively heavy spiral threads (three or four on immature shells). Umbilical callus completely, or not quite completely, filling umbilicus. Parietal callus narrow, overlapping umbilical callus. Junction of outer lip and parietal callus forming a faint gutter.
 Height 1 mim, diamter 1.5 mm (type).
 Type: USNM 561432. Paratype, USNM 561433. Paratypes, Stanford Univ.
 Type locality: 138a (Stanford Univ. locality 2656, Transistlinian Highway 1.6 ki northeast of Canal Zone boundary, Panamr'; same as USGS 16909), lower part of Gatun formation.
 This sculptured Pseudorotella is represented by nine specimens collected by T. F. Thompson from the lower part of the Gatun formation. It seems to have no known close allies.
 Occurrence: Lower part of Gatun formation middlee Miocene), locality 138a.

 Subgenus Diaerecallus Woodring, n. subgen.
Type: Teinsoira (Diaerecallus) sychrni Woodring, n. sp.
 lriocene, Gatun formation, Canal Zone.

 Small, thick-slielled, smooth or practically smooth. Suture strongly impressed. Umbilicus filled with callus, Edge of umbilical callus forming well defined ridge. Extension of parietal callus overlapping umbilical callus, deeply grooved adjoining coluiellar lip.
 Diaerecallus is characterized by the strongly impressed suture and the abrupt overlap of a grooved extension of the parietal callus. It may represent a modification of Aepystoma, or possibly of a teinostome more or less


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