296 
practicable to do so. * * * Taken as a whole, the fresh-water faunas 
of the Judith River and the Laramie are somewhat more distinct than the 
brackish-water faunas of the same formations, and with fairly complete 
collections it should not be very difficult to distinguish them in the labora- 
tory. 
When we come to compare the vertebrates of the Judith River beds 
with those of the Lance Creek deposits it becomes necessary practically 
to ignore the mammals, inasmuch as only two species of these have up to 
this time been discovered in the Judith River. These are Ptilodus pri- 
mevus and Borodon matutinus, both described by Lambe from the Belly 
River beds of British America. The former of these fossils is related to 
species of the same genus found in the Lance Creek beds and in the Tor- 
rejon, the latter genus is of undetermined relationship. 
Fishes.—Beginning with the fishes, there have been described from 
the Judith River beds eight species. In the Lance Creek beds, Converse 
County, Wyoming, Professor Williston (Science, xvi, 1902, p. 952) found 
materials which he refers to two of these species (Vyledaphus bipartitus, 
Lepisosteus occidentalis). One of these fishes, Myledaphus bipartitus, 
seems to be a ray. The rays are almost wholly inhabitants of salt water ; 
hence the persistence of this Judith River freshwater form is somewhat 
remarkable. A supposed sturgeon, Acipenser albertensis, found by Lambe 
in the Belly River beds, occurs, according to Williston, in the Lance Creek 
beds. From the Belly River beds Mr. Lambe described a remarkable 
species of fish which he called Diphyodus. Watcher states that similar 
jaws are common both in the Judith River beds of Montana and in the 
deposits of Converse County, Wyoming. From the Hell Creek beds of 
Wyoming Mr. Barnum Brown has reported the discovery of another spe- 
cies of the same genus. 
Tailed Amphibians.—Of the tailed amphibians, at all times rare fos- 
sils, Cope described from the Judith River region four species, all members 
of the genus Scapherpeton. Lambe believes that he has found one of these 
in the Belly River beds, a fact that shows the somewhat extended distri- 
bution of the genus at that epoch. Williston found one of the species in 
the Lance Creek beds and Brown reported a species from the Hell Creek 
deposits. While it is true that these fishes and amphibians are mostly 
represented by fragmentary remains, these remains are usually character- 
istic and capable of accurate comparison. That Myledaphus should reap- 
pear after an interval allowing the deposition of 1,000 feet of marine 
