Ill Carnivoha. — -MAMMALIA. Carnivora. 
cerned in the cast made by (jervais. The genus was 
first brought to liglit througli discoveries of remains 
in France. J)r. Evans and others liave since found 
six species in the iMauvaises 'Ferres of Dakota. M. 
horridus is regarded as exhibiting characters that 
indicate one of tlie most sanguinary beasts that lias 
ever existed, to our knowledge. It is indicated by 
the greater part of two skulls, together with a few 
fragments of jaws and teeth of other individuals. 
'I’he specimens of jaws and teeth have afforded us a 
view of the entire dentition of the animal, which is 
truly formidable, 'i'he powerful canine teeth are 
supplemented by the unusual number of three teeth, 
constructed nearly after the model of the single sec- 
torial tooth of other carnivorous mammals, though 
the last one alone reaches full development of tlie 
corresponding tooth in the latter. 'I’he true sectorial 
molars of the Hysenodon, the last of the series of 
teeth, are constructed like those of the Lion and 
'I’iger. 'J'hese teeth are the broadest and strongest 
of all, and combine the mechanism of the wedge and 
scissors, thereby being exceedingly appropriate for 
cutting animal tissues, even including the solid bones. 
'J’he temporal fossae are enormous, and enclose masses 
of solid muscles, which operate with exceeding force 
on the long levers of the lower jaws. 'I’he skull of 
this species measures about a foot in length. If. 
crucians is much smaller. .L half dozen imperfect 
skulls, with fragments of jaws and teeth and other 
bones, have been found, from which the species was 
established. 'I’hough small, comparatively, it ex- 
hibits the same possibilities in the dentition and 
strength of jaw that the larger has. H. cruentus 
was found in fragments at the same locality as the 
preceding. 
Mesonix is referred to the same family by Prof. 
Cope, who has indicated it by remains .found in the 
Eocene of ITew Mexico and AYyoming, associated 
with several others, which could not be seen to be- 
long to any existing family. 
Syno 2 )lotlieHum. — A fore-foot and leg of a form 
hitherto not known were found in the deposits of 
Mammoth Buttes, near South Bitter Creek, Wyom- 
ing, and named by Prof. Cope as above. One species 
only has been recognized, which is called S. lanius. 
It presents a more generalized type than others be- 
fore mentioned, resembling the ITymnas and the 
Bears. 'I’his is figured in Hayden’s c/'iAc U. 
S. Geological Survey of the Territories, 1872. Prof. 
.Marsh has described two genera from the same for- 
mation, which embrace species approaching this. 
Stypolo'phus is a genus formed by Prof. Cope from 
remains obtained by him in the Eocene of the 
Bridger group, associated with the preceding forms. 
'I'his embraces small Carnivores closely allied to the 
foregoing. S. insectivorus, S. pungens and S. brevi- 
calcaratus are indicated as species. 
Viverrams is another form allied to the latter, and 
named by Prof. Marsh. 'I'he species, Y. parvivorus, was 
determined by ITof. Cope from fragments of jaw and 
other bones found at Black’s Fork, on Green lliver. 
Icticyon. — Wallace remarks : “ Ganidm are repre- 
sented in South America by Canis and Icticyon.” 
llymnictis is a genus occurring in the Upper i\lio- 
cene deposits of Greece and in Hungary. 
lAjcmna and Hemicyon are genera partaking equal- 
ly of the characters of the Dog and Glutton ; found 
in same locality as preceding. 
Fseudocyon is allied to the Wolf and Fox families, 
and, with the two preceding forms, are from the 
Upper Miocene of Central and Western Europe. 
Fteroclon is an allied form from the beds of the 
Upper Eocene in France. 
JElurogale is another of the same period, from the 
Phosphate beds of the south of Prance. 
GaUtliylax, Gyotlieriwn and Gynoclietis were 
small, and, with the existing genus Canis, are found 
in the Upper Eocene of France. 
Arctocyon represents an animal about the size of 
a AYolf, and is regarded as a very ancient and general- 
ized form of Carnivore, which cannot be jilaced in 
any existing family. It is found in the Lower Eocene 
of France, and is thus the oldest known member of 
the Garnivora. 
Fatriofelis, Uintacyon and one already recorded 
above — the Sinopa — are animals nearly the most 
ancient of the order. 'I’hey are recognized by some 
remains found in the IMiddle Eocene of Wyoming, 
by Prof. Cope, in 1875. 'They are all of large size, 
and belong to no existing family. P. ulta was de- 
termined from portions of the lower jaw by Dr. Leidy. 
Fachymna is from the preceding locality, and is 
allied to Pterodon. 
Frototomus, from the same locality, is allied to 
Amphicyon and the Viverrida;. 
Limnocyon is a Civet-like Carnivore, with resem- 
blances to the Canine animals, and is from the same 
region as the latter. 
Machcerodus. — This is a form exhibiting enormous- 
ly developed Canine teeth. It was larger than the 
existing Lion and 'I’iger. Remains of this creature 
were found in the Miocene of Greece. It is an in- 
teresting fact that the great Carnivores wdiose re- 
mains are now found in Middle Europe are now 
entirely confined to tropical regions. 'The present 
form exhibits characters that suggest the extreme 
development of the Feline race. It is found in the 
Siwalik Hills of India, in the Upper Miocene of 
Dakota, in the Brazilian bone caves, and in the Plio- 
cene Period of temperate South America. 'I’his 
great flesh-eater, or sabre-toothed 'I’iger, as its name 
suggests, was recognized in the deposits of Dakota 
from perfect crania, on which is distinctly seen the 
lengthening downwards of the chin to receive and 
protect the enormous canine teeth. 'The upper 
canines are nearly as long as the entire lower jaw. 
It has been suggested that this is a fair example of 
the mutual correlation of structure — for offence and 
defence — of animals inhabiting the same region ; the 
powerful jaws and enormous upper canines being, 
apparently, purposely adapted for tearing up the 
large Armadillo {Glyp)todon). whose carapace or up- 
l)er shell is found in the superficial deposits of South 
America, of the same age, and is seemingly an im- 
penetrable tortoise-like armor. 'I’he Jaguar is the 
living representative of this monster. Dr. Lund dis- 
