GEOLOGY AND PALEONTOLOGY OF CANAL ZONE


County, Calif.) have not been described and the age is still unknown.
 I am indebted to R. T. Abbott for pointing out that Born's Turbo trochiformis is an earlier name for Lamarck's Trochus radians.
 Occurrence: Middle member of Caimito formation (late Oligocene), Gatun Lake area, localities 57 (Trochita? sp.), 57a (Trochita cf. T. trochijormis). Culebra formation (early Miocene), Gaillard Cut, localities 115a (Trochita? cf. T. trochiformis), 115b (Trochita cf. T. trochiformis, 116 (Trochita cf. T. trochiformis). Lower part of Gatun formation (middle Miocene), locality 136, 136a. Middle part of Gatun formation (middle Miocene), western area, locality 161c (Trochita? sp.). Miocene, California (identification doubtful). Pliocene, California, Morocco. Pleistocene, Chile, Cape Verde Islands, Morocco. Recent, Manta, Ecuador, to Valparaiso, Chile; Cape Verde Islands, Angola.
 Genus Crucibulum Schumacher
 Schumacher, Essai d'un nouveau systeme des habitations des
 vers testac6s, p. 56, 182, 1817.
 Type (logotype, Burch, Conchological Club Southern Calif.
 Proc., no. 56, p. 19, 1946): Crucibulum planum Schumacher (=Patella auricula Gmelin), Recent, Florida and West Indies.
 J. E. Gray's (1847, p. 157) designation of Patella auriculata as the type of Crucibulum is not valid in the strict sense, as Patella auriculata was not mentioned by Schumacher. Schumacher, however, based Crucibulum planum on Chemnitz's Patella auriculata without mentioning it by name. Both Crucibulum planum and Patella auriculata, given binomial standing by Dillwyn in the year when Schumacher published the generic name Crucibulum, are synonyms of Patella auricula Gmelin.
 The recent type designation by Burch, on the advice of Keen, appears to be the first valid designation. The question of possible virtual monotypy, raised by Keen, need not be considered. Whatever the status of Crucibulum rugoso-costatum, the only other species mentioned by Schumacher, may be, Crucibulum was not monotypic.
 Unidentified molds from the Culebra formation, the Alhajuela sandstone member of the Caimito formation, and the Chagres sandstone are listed as Crucibulun sp.
 Subgenus Crucibulum s. s.
 Crucibulum (Crucibulum) chipolanum Dall
 Plate 19, figures 6, 7
Crucibulum auricula var. chipolanum Dall, Wagner Free Inst. Sci. Trans., v. 3, pt. 2, p. 349, 1892 (Miocene, Florida). Crucibulum chipolanum Dall, Gardner, U. S. Geol. Survey Prof. Paper 142, p. 567, pl. 56, figs. 10, 11, 1947 (Miocene, Florida).


 Of medium size, elliptical in ventral plan. Protoconch of about 1Y rapidly enlarging whorls. Shell smooth to diameter of 1%Y to 3 mm. At that stage the shell is elliptical and the apex lies far to the rear. Sculpture consisting of closely spaced crudely roughened radial ribs, some of which bifurcate and a few of which unite as they extend outward. Right anterior border of cup sharply angulated, joined to side of shell at level far above ventral margin of cup.
 Maximum diameter 27 mm, height 16.5 mm (figured specimen).
 Type (lectotype, the specimen figured by Gardner): USNM 112783.
 Type locality: USGS 2212, Tenmile Creek, Fla., Chipola formation (early Miocene).
 Specimens from the middle part of the Gatun formation at the Gatun Third Locks excavation closely resemble Crucibulum chipolanum in characters of protoconch, sculputre, and cup. The right side of the cup of the figured specimen was uncovered, but the shell is too fragile to uncover the entire cup. Locality 155c yielded a worn incomplete specimen. It shows the same kind of cup and traces of radial ribs, but is only tentatively identified as C. chipolanum.
 C. chipolanum was described as a variety of the Recent Caribbean C. auricula (Gmelin). Undoubtedly it is closely related to that species and to the Recent Panamic C. spinosum (Sowerby). The cups of all three are similar. The sculpture of C. auricula is weaker and more varied than that of C. chipolanurn. As pointed out by Gardner, the protoconch whorls of C. auricula are wider and emerge more obtusely. Both C. auricula and C. spinosum are recorded from the Miocene of the Dominican Republic (Pilsbry, 1922, p. 385).
 A species of Crucibulum from the Shoal River formation of Florida and its Oak Grove sand member, C. chipolanum dodoneum Gardner (1926-47, p. 567, pl 56, figs. 18-20, 1947), has coarser sculpture than C. chipolanum. It presumably is not closely related, however, to C. chipolanum, as its cup is attached to the side of the shell at the level of the ventral margin of the cup.
 Dall designated no type material for C. chipolanun. In his description he mentioned only one locality: the Chipola River, a mile below Baileys Ferry. He also examined and identified, however, specimens from the nearby Tenmile Creek locality, a mile west of Baileys Ferry. The specimen from the Tenmile Creek locality figured by Gardner is herewith designated the lectotype.
 Occurrence: Middle part of Gatun formation (middle Miocene), eastern area, localities 155, 155b, 155c (including a doubtfully identified worn specimen). Chipola formation (early Miocene), Florida.


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