BULLETIN FLORIDA STATE MUSEUM


 The dental nomenclature used in this paper and illustrated in Figure 1 follows Stir-
ton (1941) and Skinner and Taylor (1967). The postcranial terminology follows Camp
and Smith (1942), Sisson and Grossman (1953), Barone (1966), Sondaar (1968), and Hus-
sain (1975).
 LOCALITIES
 Nannippus phlegon is now known from four localities in Florida (Fig. 2). Except for
Haile XVA, which was collected in an isolated fissure, these localities represent at least
several local sites in an area. This horse had previously been reported from only the
first two localities listed below.
 Santa Fe River I, IA, IB, and 4A: About 10 m underwater and consisting of collec-
tions found in deeper holes along the river bottom or in situ in the bank (IB), Columbia
County, localities collected by B. Waller, R. R. Allen, C. E. Ray, J. H. Hutchinson, S. D.
Webb, K. M. Ainslie, J. S. Robertson, and J. S. Waldrop (see Brodkorb 1963, Hibbard et
al. 1965, Webb 1974).
 Haile XVA: On land formerly owned by Parker Brothers Limestone Products, Inc.,
near Haile, Alachua County, locality collected by P. Kinsey, J. S. Robertson, S. D.
Webb, and R. R. Allen (see Webb 1974, Robertson 1976).
 Sarasota: A series of at least three'localities in non-marine sediments that overlie the
Pinecrest Formation west of Sarasota city, Sarasota County, locality collected by J. S.
Waldrop, 1976-1977.
 Port Charlotte: Canal spoil dumps on north edge of Port Charlotte, Charlotte Coun-
ty, localities collected by D. Wilson and field crews from the USNM during numerous
field seasons, M. C. Thomas, and J. S. Waldrop in 1967; also a locality of Roy H.
Burgess "collected from a canal bank (in situ) near Port Charlotte, Florida" (Skinner
1972:117).
 For the Sarasota and Port Charlotte localities, detailed geographic and geologic
data are available in Waldrop's field notes.

 SYSTEMATIC PALEONTOLOGY
 CLASS MAMMALIA LINNAEUS 1758
 ORDER PERISSODACTYLA OWEN 1848
 FAMILY EQUIDAE GRAY 1821
 Genus Nannippus MATTHEW 1926
 Nannippus phlegon (HAY) 1899
 FIGURES 1-14, TABLES 1-10

 HOLOTYPE.-BEG 18586, fragmentary lower molar.
 TYPE LOCALITY.-Crawfish Draw, Mt. Blanco, Crosby County,
Texas Panhandle (see discussion of type locality in Skinner and Hib-
bard 1972). The local fauna from Mt. Blanco typifies the Blancan
North American Land Mammal Age (e.g. Schultz 1977).
 DISTRIBUTION.-Blancan (Pliocene, sensu Berggren and Van
Couvering 1974, Lindsay, Opdyke, and Johnson 1975) of Florida,
Texas, Kansas, Nebraska, and Arizona (see references in
Introduction).
 DIAGNOSIS.-Small and gracile hipparion. No preorbital facial
fossa. Elongate rostrum and symphysis. Teeth very hypsodont, even


Vol. 25, No. 1