EXTINCT MAMMALIA OF NORTH AMERICA. 429 



It is by no means certain that the remains from the eocene formations of South 

 Carolina, described by Gibbes under the name of Dorudon and Basilosauru-s serratus, 

 belong to the same animal, as the vertebrae from Alabama, referred by Miiller 

 together with the former remains, to Zewjlodon Irachyspondylus. Admitting, however, 

 that they are the same, the comparatively short vertebrjB of the latter would sepa- 

 rate the genus from Zeuglodon, or Basilosaurus as 1 prefer to call it, and I therefore 

 have adopted the generic together with the earlier specific name of Dr. Gibbes. 



Eocene of South Carolina, Alabama and Louisiana. 



Four comparatively well preserved and isolated teeth, sent to me for exami- 

 nation by Prof F. S. Holmes, of Charleston, and obtained by the late M. Tuomey 

 from the eocene formation of Alabama, appear to belong to the Zewjlodon hrachyspon- 

 dylm of Miiller, which I have viewed with him as synonymous with the Dorudon 

 serratus of Gibbes. 



The teeth, represented in figures 2-5, plate XXIX, consist of a canine, a premolar 

 with connate fangs and two molars with separate fangs. 



The canine tooth, represented in figure 2, has nearly the form and size of 

 that described and figured by Dr. Gibbes as pertaining to Dorudon, or Basilosaurus 

 serratus. The crown bears a close resemblance to that of the canine of a Bear. 

 In the specimen it is unworn, is compressed conical, with a rather blunt apex and 

 with the borders acute. The enamel is strongly wrinkled on both surfaces. The 

 fang forms a rather abrupt angle with the crown, and is less robust than in the 

 specimen represented in figure 3, plate IV, of Dr. Gibbes' plate. It is moderately 

 tapering, compressed and solid; the broken end exhibiting nothing but a minute 

 orifice of the dental canal. 



The premolar, represented in figure 3, is a less robust tooth than the preceding. 

 It has the summit of the crown worn blunt so as to expose the dentine, and the ends 

 of the fiings are broken off. The crown is considerably shorter and more com- 

 pressed than that of the canine, but is rather broader. The enamel is wrinkled, 

 though not quite so strongly as in the canine. The fangs are connate through- 

 out as well as solid, exhibiting no trace of dental canals. 



The molar, represented in figure 4, from an intermediate position in the series, 

 nearly corresponds in size with those referred by Dr. Gibbes to Dorudon serratus, 

 but in appearance resembles more those of Basilosaurus cetoides than it does the 

 figures of the former represented in Dr. Gibbes' plate IV. In Dr. Gibbes' figures 

 the enamel investment of the molars is represented as of remarkable shallowness, 

 probably due to an attempt at perspective drawing by the artist. Dr. Gibbes states 

 that the enamel in the teeth extends an inch in depth from the summit, whereas in 

 the figures it is represented to be from seven to nine and one-half lines. In a plaster 



