art. 16, TWO SQUALODONTS FROM MARYLAND—KELLOGG. 35 
SQUALODON TYPICUS, new species. 
See Delphinoides gratelupi Pedroni. 
DIOCHOTICHUS VANBENEDENI (Moreno). 
Notocetus Van Benedeni Moreno, F. P., Revista de Museo de La Plata, vol. 3, 
pp. 397-400, pl. 11, 1892. 
Type specimen.—Consists of a skull in a fair state of preservation, 
mandibles, and a part of the vertebral column. Type in the ‘‘ Museo 
de La Plata,’’ Argentine Republic. 
Type locality—Port Madryn on Bahia Nueva, Chubut Territory, 
Patagonia, latitude 42° 30’ south. Julian beds or Lower Miocene. 
Subsequent allocation.—In February, 1894, Ameghino* proposed 
Diochotichus as a new generic name for Notocetus Moreno because 
he considered the later name to be preoccupied by Nottocetus 
Ameghino.® An additional name, Argyrodelphis, was inadvertently 
proposed for Moreno’s specimen by Lydekker. * 
This form is considered to belong to the family Physeteridae by 
Winge ” and to represent the most ‘primitive genus of the Xiphiini. 
A study of the Pescadores skull, however, convinced True*® that 
Diochotichus belonged to the family Squalodontidae, or, in other 
words was a squalodont with simple teeth, having single roots and 
conical crowns. The posterior teeth are furnished with minute fore- 
and-aft cusps. It shares the following features with Squalodon. The 
orbital plates of the maxillae are shorter anteriorly than the thicker 
frontal plates, leaving a considerable portion of the latter exposed in 
front. The mesorostral channel is open proximally though nearly 
closed distally by the approximation of the overhanging premaxillae. 
The zygomatic processes are large, thick, and oblong. The premax- 
illae are expanded anteriorly and abbreviated posteriorly. <A pair 
of large ophthalmic foramina are also present at the end of the me- 
sethmoid gutter. The presence of these foramina in both Squalodon 
and Diochotichus does not necessarily indicate relationship, for they 
occur also in Eurhinodelphis. Furthermore, it differs from Squalodon 
in that the posterior margins of the temporal fossae overhang and 
project beyond the plane of the condyles. 
A somewhat different view of the relationships of Diochotichus was 
advanced by Dal Piaz.** This writer proposed a new family, Squa- 
lodelphidae, to include the Italian Squalodelphis Ee the Patagonian 
Diochotichus. 
84 Ameghino, F., Enum. Synopt. Mamm. Foss. Eocén. Patagonie, p. 182, 1894. 
55 Ameghino, F., Revista Argentina Hist. Nat., vol. 1, entr. 3a, p. 167, 1891. 
‘6 Lydekker, R., Anal. Mus, La Plata, Palaeont. Argentina, vol. 2 for 1893, art. 2, pp. 12-13, April, 
1894; Natural Science, vol. 4, No. 24, p. 126, February, 1894. 
87 Winge, H., Smithson. Mise. Coll., Washington, D. C., vol. 72, No. 8, Publ. 2650, p. 38, 1921 (trans- 
lation by G. S. Miller, jr.). 
8 True, F. W., Bull. Amer. Mus. Nat. Hist., vol. 28, art. 4, pp. 19-32, pls. 1-5, 1910; Dal Piaz, G., 
Gli Odontoceti del Miocene Bellunese. Parte Terza. Squalodelphis fabianii. Mem. Ist. geol. R. Univ. 
di Padova, vol. 5, pp. 1-34, pls. 1-5, 1916. 
