1895.] Geology and Paleontology. 573 
Müller is in cranial characters much like Mystacoceti of the genus 
Cetotherium, and that it is probable that the latter were derived from 
the forms by the loss of their teeth. The structures of the mandibular 
rami of various species show the transitions from such a form to those 
of the right whales. Deriving the Balænidæ then from a form like 
that of the new genus Agorophius (type Zeugloden pygmeus Miill.), we 
have a succession of genera in which the gingival groove and dental 
canal show various stages of roofing, fusion or obliterati The genera 
of the Neocone beds were defined as follows. 
I. Gingival groove distinct from dental canal. 
Gingival groove open ; Genus not discovered. 
Gingival groove overoofed ; Siphonocetus Cope. 
II. Dental canal not distinct ; gingival groove open. 
Gingival tubules wanting ; Ulias Cope. 
Gingival tubules present ; Tretulias Cope. 
III. Gingival groove and dental canal fied. 
Common canal roofed, and perforated by gingival tubules ; 
Cetotherium Brandt. 
The type of Siphonocetusis Balæna prisca Leidy. 8S. expansus Cope, 
and S. clarkianus Cope, sp. nov. belong to it. The type of Ulias is U.. 
moratus Cope sp. nov. - The type of Tretulias is T. buccatus Cope, sp. 
nov. To Cetotherium are referred C. pusillum Cope, C. crassangulum 
Cope sp. nov., C. polyporum Cope, and C. cephalus Cope. All the 
species of Balænidæ referred to are from the Yorktown (Middle) 
Neocene beds of Maryland, Virginia and N. Carolina. 
Two New Species of Dinictis from the White River Beds. 
—The primitive saber-toothed cats are already represented in the 
genus Dinictis by three species; D. felina Leidy, D. cyclops Cope and 
D. squalidens Cope. To these may be added the two species described 
in this article, D. fortis and D. bombifrons. With the exception of D. 
cyclops from the John Day Beds of the Lower Miocene, the species are 
confined to the White River or Oligocene. Until the division of the 
White River,’ no account of horizons was taken in collecting, but from 
the specimens at hand the range of the different species is indicated as 
follows: D. fortis, Titanotherium and Lower Oreodon Beds, D. bom- 
bifrons Lower Oreodon Beds, D. felina, Lower Oreodon to the Proto- 
ceras Beds. 
1 Divisions of the White River or Lower Miocene of Dakota, by J. L. Mort- 
man, Bulletin American Museum, Nat. Hist., Vol. V, June 27, 1893. 
