374 0. C. Marsh on a new species of fossil Horie: 
desires, in concluding, to express his thanks to Gen, W. Snyder, 
Superintendent of the Union Pacific Railroad, for his kind 
assistance in securing the Siredons at Lake Como in August 
last ; to-his friend Prof. E. D. Cope, of Philadelphia, for vari- 
ous suggestions in regard to the subject here treated of, and 
likewise to his friend, Prof. George F'. Barker, of Yale College, 
for careful observations on the specimens while he was tempo- 
rarily absent from New Haven. 
Yale College, Oct. 10th, 1868, 
EXPLANATION OF THE PLATE. 
Figure 1. Undeveloped larva of Amblystoma mavortium Baird, hitherto known 
as Siredon lichenoides Baird. Animal represented as in motion, with 
external branchize thrown back (} natural size). 
Figure 1a. Dorsal view of same specimen when at rest, with branchis fully er 
pande 
Figure 1b. View from below, showing arrangement of maxillary and palati 
series of larval teeth and inner nostrils of same species (natural size) 
Figure 2. Amblystoma mavortium Baird, (variety A. maculatum Ball), partially 
developed from Siredon lichenoides Baird, with remnants of external - 
branchize, and internal arches, still retained (} natural size). 
Figure 3. Amblystoma mavortium Baird, developed from Siredon 
Baird: metamorphosis apparently completed (4 natural size), 
Figure 3a. Maxillary and palatine series of teeth of Amblystoma mavortium Baird, 
after metamorphosis (natural size). 
Arr. XXXVIIL—Notice of a new and diminutive spects 1 
fossil Horse (Equus parvulus), from the Tertiary of 
braska; by Prof. O. C. Marsu, of Yale College. | 
In a small collection of fossil eda 6p —— obiained 
the writer during the past summer in the 35 ie ieresh, 
i: ye 5 BGwe ne 
they indicate a new species of fossil horse, page a An 
mi 
of a well, they had been thrown out from a depth wile pee 
eight feet. This locality has since attained considera baer 
riety, from the fact that the remains then found were ‘i arious 
ced to be human by those who first examined them, #2 : 
. ° 0 wud 
already given elsewhere.* ae 
* National Academy of Sciences. Northampton Meeting, Avg: 
. 
