Arr. 16. TWO SQUALODONTS FROM MARYLAND—KELLOGG. 5 
the writer wishes to acknowledge his indebtedness to John C. Merriam, 
president of the Carnegie Institution of Washington, for the assist- 
ance and kindly interest he has shown in this problem. 
Acknowledgments are due to the following for correcting or con- 
firming the age determinations of those forms which occur in their 
respective countries: Prof. Giorgio Dal Piaz, Museo Geologico dell’ Uni- 
versitaé di Padova, Italy; Prof. Giuseppe Stefanini, Museo Geolog- 
ico, Firenze, Italy; Dr. Federico Sacco, R. Politecnico, Gabinetto di 
Geologia, Castello del Valentino, Torino, Italy; Dr. H. Gerth, Rijks 
Geologisch-Mineralogisch Museum, Leiden, Holland; Prof. Othenio 
Abel, Paleobiologischer Lehrapparat der Universitat, Wien, Austria; 
and J. McDonald, acting director, Dominion Museum, Wellington, 
New Zealand. Acknowledgments also are due to George P. Merrill 
and T. Wayland Vaughan. 
Before describing the specimens from the Calvert Cliffs, Maryland, 
it was necessary to examine most of the literature relating to the 
animals in question, which had been accumulating during the past 
84 years. Since Grateloup recorded the occurrence of Squalodon in 
France nearly 50 names have been proposed for remains of cetaceans 
which were assumed to be squalodonts at some time after their origi- 
nal publication. A review of these forms follows. It will be noticed 
that no attempt is made to offer a full bibliography for each species, 
and that only such references are given as are considered to be perti- 
nent to the present study. In considering their claims to recognition 
the specific names may best be taken up alphabetically. 
NOMENCLATURE. 
MICROCETUS AMBIGUUS (Meyer). 
Phoca ambigua MuenstTER, G. G. Von, Neues Jahrbuch fiir Mineralogie, Stutt- 
gart, p. 447, 1835 (nomen nudum).—MEYER, H. Von, Beitriige zur Petrefacten- 
Kunde (herausgeg. von Georg. G. zu Muenster), Bayreuth, vol. 3, p. 1, pl. 7, 
figs. 1-8, 1840 [Giebel, C. G., Odontographie, Leipzig, pl. 36, figs. 10, lla, 118, 
14, 1855].—Motutn, R., Sitzungsber. math.-naturwiss. Cl. Kais. Akad. der Wis- 
senschaften, Wien, vol. 35, No. 8, p. 118, 1859. 
Type specimen.—Consists of two one-rooted premolars and two 
two-rooted molars, a fragment of a rib, and a dorsal vertebra. Type 
in the ‘ Paliontologische Sammlung” at Munich, Germany. 
Type locality—Found 30 feet below the surface in the Tertiary 
marl of the Osnabriick Basin near Biinde, Oldenburg, Germany. 
Upper Oligocene. 
Subsequent allocation.—This form belongs in the group of squalo- 
donts characterized by Neosqualodon Dal Piaz according to Abel.® 
The absence of accessory cusps on the anterior cutting edge of the 
molars*® and the shape of those on the posterior edge shows clearly 
8 Abel, O., Mém. Mus. Roy. Hist. Nat. Belgique, Bruxelles, vol. 3, footnote, p. 66, 1905. 
§ Meyer, H. von, Beitrige zur Petrefacten-Kunde, Vol. 3, pl. 7, figs. 1a, b; 2a, b, c’ 3, 1840. 
