CHAP. VII.] 
MAMMALIA OF THE NEW WORLD. 
133 
belong to the Primates; so that no less than twelve genera of these 
animals are recognized by Mr. Marsh, who classes them in two 
families — Limnotheridse, comprising the genera Limnotherium , 
(which had larger canine teeth), Tkinolestes, Telmatolestes, Mesa- 
codon . , Bathrodon , and Antiacodon of Marsh, with Notharctos , 
Ilipposyus, Microsyops, and Falceacodon previously described by 
Leidy ; — and Lemuravidas, consisting of the genera Lemuravus 
(Marsh) and Hyopsodns (Leidy). The animals of the latter 
family were most allied to existing lemurs, but were a more 
generalized form, Lemuravus having forty-four teeth, the greatest 
number known in the order. These numerous forms ranged from 
the size of a small squirrel to that of a racoon. It is especially 
interesting to find these peculiar lemuroid forms in America, 
just when a lemur has been discovered of about the same age 
in Europe ; and as the American forms are said to show an 
affinity with the South American marmosets, while the European 
animal is most allied to a West African group, we have 
evidently not yet got back far enough to find the primeval 
or ancestral type from which all the Primates sprang. 
About the same time, in the succeeding Miocene formation, 
true monkeys were discovered. Mr. Marsh describes Laopithe- 
cus as an animal nearly the size of the largest South American 
monkeys, and allied both to the Cebidse and the Eocene Linrno- 
tlieridse. Mr. Cope has described Menotherium from the Mio- 
ceue of Colorado, as a lemuroid animal, the size of a cat, and 
perhaps allied to Limnotherium. More Miocene remains will, 
no doubt, be discovered, by which we shall be enabled to trace 
the origin of some of the existing forms of South American 
monkeys ; and perhaps help to decide the question (now in dis- 
pute among anatomists) whether the lemurs are really Primates, 
or form an altogether distinct and isolated order of mammalia. 
Insectivora. — This order is represented by comparatively few 
forms in the tertiary beds, and these are all very different from 
existing types. In the Upper Miocene of Dakota are found 
remains indicating two extinct genera, Lepictis and Ictops. In 
the Miocene of Colorado, Professor Cope has recently discovered 
four new genera, Isacis ; allied to the preceding, but as large as a 
