See ATEA ee. RUNE Ph ee EER A I NR SAC se Om UT INIRE 
* 
1894.] Geology and Paleontology. 595 
of the Artiodactyla except Oreodontide and Tylopoda, of the true 
Carnivora, and the Monkeys (except the S. American). North 
America was the home of the Perissodactyla and Amblypoda, and the 
ancestors of the monkeys and carnivora, during that time. 
The Skull of Pisodus owenii.—It is now a well-established fact 
that many types of Teleostomous fishes have undergone very little change 
since the Eocene, or even since the latter part of the Cretaceous period. 
Several well-defined genera seem to date back thus far, and others are 
represented by forms that differ in but small particulars. Moreover, 
a few of the most remarkable specializations in piscine skeletal anato- 
my chatacterizing the existing faüna are already recognizable in certain 
closely related Eocene types, and the progress of discovery is continu- 
ally adding to the number of known examples. A most striking new 
case has been lately met with by the present writer among the fishes 
from the London Clay (Lower Eocene), and this forms the subject of 
the following notes. 
So long ago as 1845, Sir Richard Owen described and figured the 
tritural dentition of an unknown fish form the London Clay of the Isle 
of Sheppey under the name of Pisodus oweni (ex. Agassiz MS.). The 
original specimen is preserved iri the Museum of the Royal College of 
Surgeons, and exhibits an ovate pavement of small rounded or poly- 
gonal teeth firmly fixed in shallow sockets upon a plate of true bone. 
Appearances suggested to Sir Richard Owen that the fossil had been 
attached to another bone of the skull, most probably, as in Glos- 
sodus and Sudis, to a median bone of the hyoid system. Agassiz, who 
first examined the specimen, supposed it might pertain to a so-called 
Pyenodont Ganoid; and in Owen’s Paleontology (edit. 2, 1861, p. 
174) Pisodus is also doubtfully quoted as a “Ganoid” of uncertain 
position. 
It now appears from a nearly complete skull in the British Museum 
that the problematical fossil in question is the parasphenoid dentition 
of a fish remarkably similar in eranial characters to the recent Clupeoid 
"Albula. The fact has already been incidentally mentioned in a record 
of the discovery of Pisodus in the Middle Eocene of Beligium; and it 
only remains to justify, by a detailed description and figures, the recog- 
nition of an Albula-like fish at so remote a period as that of the Lower 
Eocene. Dr. Shufeldt's admirable description of the skull of the 
recent Albula vulpes fortunately suffices for requisite comparison. 
(Dr. Smith Woodward in Ann. Mag. Nat. Hist. Ser. 6, Vol. XI, 1893.) 
