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formations, Dominican Republic. Pliocene, Caloosahatchee
mar·l, Caloosahatchee River, Shell Creek, Alligator Creek, and
Myakka River, Fla. Pliocene undifferentiated, Costa Rica and
Trinidad. Recent, New England to Bahia, Brazfl, and east to
Bermuda in 3 to 175 fathoms ; dredged by the Woods Hole Survey
in the eastern half of Vineyard Round and Buzzards Bay
in 3 to 13 fathoms chiefly on gravel and sand bottoms.
Family CAECIDAE
Genus CAECUM Fleming
1813. Caeoum Fleming, Brewster's Edinburgh Encyclopedia,
vol. 7 ( 1), p. 67 (fide Sherborn).
Type by subsequent designation (Gray, Zool. Soc. London
Proc., pt. 15, p. 203, 1847) : Dentalium trachea Montagu. Re­
-cent, from the British Isles to the Mediterranean.
Shell a small, gently arcuate tube. Protoconch cadu­
-cous, planorboid, coiled two or three times. Nuclear
and adolescent shells successively outgrown and dis­
·Carded; a septum or "plug" serving to close the posterior
extremity of the shell. Form and position of
"'plug" constant and characteristic of the species.
Outer surface of arcuate adult tube dorsal, the inner
-surface ventral. Adult shell smooth, axially sulcate,
.annulate or reticulate. Aperture circular, entire.
The genus is rather abundant in the Tertiary and
more than a hundred species have been listed from
the warm waters of the Recent seas.
Caecum flemingi Gardner and Aldrich
Plate 28, figure 26
1919. Caecttm flemingi Gardner and Aldrich, Acad. Nat. Sci. Philadelphia
Proc., vol. 71, pt. 1, pp. 17-53, 4 pls.
Shell a gently arcuate tube, slightly larger at the
.anterior end than at the posterior. Surface smooth
-except for microscopically fine, irregular, incremental
striae. Plug ungulate, a minute, truncated cone set
dorsal to the median vertical. Anterior aperture oblique
to the horizontal axis, the margin faintly, but perceptibly,
contracted at the obscure apertural ring.
Dimensions of holotype: Height, 3.7 mm.; diameter
of anterior aperture, 1.0 mm.; diameter of posterior
aperture, 0.8 mm.
Holotype: U.S.N.M. 325448.
Type locality: Neills Eddy Landing, Cape Fear
River, Columbus County, N.C. Waccamaw formation.
No a pert ural ring has been detected in C. ·virgi­
·niamurm Meyer (pl. 28, fig. 17), of the Yorktown formation.
Though not true of the figured examples, the
Yorktown forms average a little larger, and are perhaps
a little less arcuate than Caecum flemingi. Caecum virginianum
has been recovered from the Yorktown formation
at Yorktown and at Benns Church in Isle of
Wight County, Va., and from the Yorktown at Rock
Landing in Craven County, N. C.
Another unsculptured species, the minute Caecum
glabrwm Montagu (pl. 28, fig. 19) was reported from
the Yorktown by Meyer, but t!1e report has not been
verified. Caecum putnanwnse Mansfield, 1924, is also
PART 2. SCAPHOPODA AND GASTROPODA 203
minute (2.5 millimeters in height), and the plug is
mammillate instead of ungulate.
Distribution: North Carolina: Waccamaw formation, Neills
Eddy Landing on the Cape Fear River, 3 miles north of Cronly,
Columbus County.
Outside distribution: Miocene, Duplin marl at the Muldrow
Place, 5 miles southeast of Mayesville, Sumter County, S. C.
Caecum regulare Carpenter
Plate 28, figure 18
1858. Caecum regulare Carpenter, Zool. Soc.· London Proc., p.
428.
1892. Caecum regulare Carpenter. Dall, Wagner Free Inst. Sci.
Trans., vol. 3, pt.' 2, p. 299.
1930. Caecum regulare Carpenter. Mansfield, Florida Geol.
Survey Bull. 3, p. 102, pl. 14, fig. 5.
Caecum regulare is a short squat species with a low
curvature, expanding slightly toward the anterior extremity.
The shell is closely annulated, usually with
20 to 25 rings, regularly spaced except near the aperture
where they become wider and less crowded. The
apertural ring is heavier than those behind it, wider
and set apart by a wider interspace. Within the ring
is a thin and narrow flange. The plug is low and
mucronate near the dorsal margin.
Dimensions of figured specimen : Height, 3.0 mm.;
diameter at anterior extremity, 0.7 mm.
Figured specimen: U.S.N.M. 325449.
Locality of figured specimen : N eills Eddy Landing,
Cape Fear River, Columbus County, N.C. Waccamaw
formation.
Mansfield (U. S. Nat. Mus. Proc., vol. 66, no. 2259,
p. 50, pl. 8, fig. 6, 1925) described a much· smaller but
similarly sculptured species, 0. properegulare, from the
Brasso beds of Trinidad; Caecum floridanrt_tm Stimpson
(pl. 28, fig. 27) and the subspecies compactum Dall
are more closely annulated than 0. regulare and exhibit
a faint and more or less fortuitous longitudinal striation.
0 aecum patuxentium Martin, from the Chop tank formation
of Maryland, is likewise more closely annulated
but lacks the longitudinal striation of C. floridanum.
Caecum regulare was apparently established along the
Atlantic seaboard not later than the upper Miocene.
Mansfield reports it from the Cancellaria zone of the
Choctawhatchee formation in Florida. In the Recent
seas the American records are ·restricted to the West
Indies. '
Distribution: North Carolina: Yorktown formation, ?Rock
Landing on the Neuse River, Craven County. Waccamaw formation,
Neills Eddy Landing, 3 miles north of Cronly, Columbus
County.
Outside distribution: Miocene, Choctawhatchee formation,
Cancellm·ia zone in Leon and Washington Counties, Fla. Pliocene,
Caloosahatchee marl, Caloosahatchee River, Shell Creek,
and Alligator Creek, Fla. Recent, West Indies ; reported also
from Singapore and Australia, but such records should be carefully
checked.