GEOLOGY AND PALEONTOLOGY OF CANAL ZONE


specimens that show it have thin enamel, except on the later part of the body whorl, where the sculpture gradually disappears under the thicker coat of enamel. Fourteen specimens from the type locality that are assigned to T. spermatia are exceptionally large as compared with scores of apparently mature specimens, like the type. As shown on plate 17, figure 31, the tip of the spire of this relatively large form is covered with a thin glaze of enamel. These 14 large specimens, which do not intergrade with the much more abundant smaller apparently also mature form, may represent a different species. If so, however, immature shells of the large and the small species have not been distinguished and apparently are indistinguishable.
 Species more or less closely resembling Teinostoma spermatia have been living in American waters since Eocene time. The very similar T. tectispira (Pilsbry, in Olsson and Harbison, 1953, p. 417, pl. 50, figs. 6-6c), a Pliocene species from Florida, has no trace of spiral sculpture. T. spermatia is more depressed and more elongate in dorsal outline than T. angulatum (Gabb) (Pilsbry, 1922, p. 398, pl. 37, figs. 1, la, 1b), and even the large form of T. spermatia is a little smaller. T. angulatum, which is found in the Cercado formation of the Dominican Republic, has very faint closely spaced spiral striae. Species similar to T. spermatia are living in both western Atlantic and eastern Pacific waters. T. cryptospira (Verrill) (Bush, 1897, p. 118, figs. 1, 2) ranging from Cape Hatteras to Florida, is more circular in dorsal outline. T. cecinella Dall (1919, p. 369), a species from Lower California, is more elongate in dorsal outline, larger, and has a thicker shell.
 Toula's Teinostoma cf. T. carinatum may be T. spermatia, though his illustrations show an exposed spire and a peripheral carina. Pilsbry (in Olsson and Harbison, 1953, p. 415), however, thought it is very similar to the Recent T. carinatum (d'Orbigny).
 Occurrence: Middle and upper parts of Gatun formation (middle Miocene). Middle part, eastern area, localities 146, 147b, 147f, 147g, 147h, 147i (identification doubtful), 153a. Upper part, eastern area, locality 177.
Teinostoma (Idioraphe) angulatum trochalum Woodring, n.
 subsp.
 Plate 17, figures 4-6
 Small, moderately depressed, dome-shaped. Periphery moderately angular on early part of body whorl, rounded on later part. Spire partly concealed by overlap of body whorl and glaze of enamel. Umbilical and parietal callus thick and coalescing.
 Height 1 mm, diameter (incomplete) 1.7 mm (type).
 Type: USNM 561431; paratypes, Stanford Univ.


 Type locality: 137 (USGS 16911, Transisthmian. Highway, 1.7 km northwest of Sabanita, Panamd), lower part of Gatun formation.
 This teinostome, found in the lower part of the Gatun,4 formation, is considered a small race of T. angulatum (Gabb), the type of Idioraphe, from the Miocene of the Dominican Republic (Pilsbry, 1922, p. 398, pl. 37, figs. 1, 1a, 1b). Gabb's specimens were collected at an unknown locality in the Dominican Republic. Specimens from the Cercado formation-Maury's T. sandomingense, (Maury, 1917, p. 156, pl. 24, fig. 24)-evidently are conspecific, although the early part of the body whorl" of the type has a more sharply angulated periphery. T. angulatum trochalum is smaller and lacks spiral sculpture. T. umbilicatum (Lea) (Mansfield, 1930, p. 134, pl. 20, figs. 1-3) and other Tertiary species from southeastern United States, as well as the Recent T. cryptospira (Verrill), have a less angular periphery.
 Occurrence: Lower part of Gatun formation (middle! Miocene), localities 136a, 137, 138a.
 Subgenus Aepystoma Woodring, n. subgen.
Type: Teinostoma (Aepystoma) andrium Woodring, n. sp., Miocene, Gatun formation, Panam6 and Canal Zone.
 Of medium size, thick-shelled, spire moderately de-. pressed, exposed. Smooth or sculptured with punctate fine spiral striae. Umbilical and parietal callus thick, more or less coalesced. Callus filling umbilicus on mature shells.
 The subgeneric name Aepystoma is proposed for a group of thick-shelled teinostomes that have an exposed spire and callus-filled umbilicus. Fossil and Recent Panamic species allied to Teinostoma andrium have been assigned to the subgenus Pseudorotella by Pilsbry and Olsson. Pseudorotella, however, has a smaller and thinner shell and less depressed spire.
 Teinostoma (Aepystoma) andrium Woodring, n. sp.
 Plate 17, figures 40-42; plate 18, figures 9-11
 Of medium size, thick-shelled, dorsal surface slightly domed. Periphery rounded on later part of body whorl, faintly and bluntly angular on early part. Sculpture of microscopically punctate faint spiral striae, for most part concealed on body whorl of mature specimens by glaze of enamel. Umbilical and parietal callus thick and coalescing.
 Height 2 mm, diameter 4.7 mm (type).
 Type: USNM 561315; paratype, Stanford, Univ.
 Type locality: 137 (USGS 16911, Transisthmian Highway, 1.7 kin northwest of Sabanita, Panam ), lower part of Gatun formation.
 Teinostoma andrium is by far the largest of the Gatun teinostomes. The sculpture is distinct only on early


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