[Vol. r:. Mo. I
��did uot add to tbis seclioa of hia introduction a general survey of the animal life in each of the periodB which he afterwanla treats in dc< tail. Such a Biimniary would have been ex- ceedingly useful.
Before examining the book in detail, it nill be of advnnlage to direct the reader's atten- tiOQ to Dr. Hajden's summaiv of " the most important contributions to paleontology and evolution," contained in his letter of trans- mittal of the volume before ue. These are: 1°. The discovery of the Puerco fauna. Tbis includes the discovery and description of three new famdiee of a new order (the Taxeopoda), and a new sub-order (the Taligi-ada); also llie discovery of the Plaginulns type (of the Jurassic), and other marsupials, and of a genus of Laramie saurians. 2". The discov- ery of complete remains of the Wasatch ly|>es, Phenacodus and Corj'phodon. "The light thrown on the phjlogeny of the Ungulala by this discovery exceeds that derived from all Other sources together," 3°. Tbe new classi- fication of the lower clawed mammals, founded on the analyses of a great number of new gen- era and species. 4". The restoration of the four-toed Wasatch horse, Hyi-aeotherium. 5°. The restoration of the Bridger genera, Hyra- chyus and Triplo])us, (1°, The determination of the systematic relatious of the Dinocerata.
Turning, now, to the body of the work, the first chapter to demand notice is that on the fishes. The shales of Green River, Bear River, and Florissant, Col., have long been famous for their abundance of fish-remains. Oar knowledge of these forms is almost en- tirely due to Professor Cope, but hitherto he has figured none of tbem. lu the present vol- ume there is a very welcome series of plates that illustrates all the types. It is a pity that Professor Cope lias adopted the classification he nses, which, being founded entirely on the skeleton, and ignoring the structure of the soft parts, is necessarily imperfect and mis-
��Perhaps Professor Cope's most signal ser- vice to paleonlol<^y is his discovery of the exceedingly curious and interesting Puerco fauna, the earliest known from any tertiary formation. This assemblage of mammals is of extraoi-dinary interest, both to the morpho!- (^st and the geologist, and goes a long way towards bridging over the gap between the ter- tiar)' and mesozoic ages. The characteristics of this fauna were given above, but we must again insist on the immense value of its dis- covery.
In the Wasatcb, the second epoch of the
��eoaene, we are presented with a no less inter- eating series of mammals and reptiles. Tbe only full account extant of AmericaD tertian' turtles and crocodiles is here given. Further, our kuowledge of the Wasatch mammals is almost altogether owing to Professor Cope. whose explorations of the Big Horn basin in Wyoming yielded such extensive collodions. The cliaptera on the ungulates of this forma- tion are of especial imiiorlance. The study of these has confirmed the author's prediction, made in 1873, that the earliest ungulates would prove to be five-toed and plantigrade, and has enabled bim to construct a scheme of all the ungulate series, which, however we may diSer as to its details, must be admitted to be a masterly presentation, and full of most valuable suggestions. These chapters, ttiut, esi>ecially the descriiitions of the skeletous €#< Periptyehus from the Puerco, and the Wasat«& genera Phenacodus and Hyracotberium Owen (Orohippus Marsh), of which Professor Cope gives the first complete account, are to be par- ticularly commended to careful study,
A very welcome section of the Iwok is that on the order Amblypoda, which includes the Dinocerata and the Coryphodons. This order, proposed in 1873 by Professor Cope, has n- oenLly been adopted under the name of Aat blydactyla by Professor Marsh. Tbe lattsr^i work OQ the Dinocerata is so much fuller and more complete than Professor Cope's chapters on them, that we need not stop to consider the latter, except to mention the curious Bathj- opsis. But nearly all that is known of the Coryphodons is due to Professor Cojje's labors, and the value of his results in this field it ia dilfloult to exaggerate.
Professor Cope has brought order out of the chaos of the small mammals which abound in the eocene, and which, with great diversity, pass into each other by imiierceptible gradfr- tions. He groups together the early Seah- eatcrs — which were not ti-ue carnivores, but small-brained forms allied to the insectivores — ' under the name Creo<lonta. giving in many cases very complete accounts of their BtnuH ture, and indicating the forms from i ' ' ' descended the various families of the carnivores. The same service has been doafr for the primitive lemurs, the most interesting. of which is the little Wasatch Anaptomorphua homuncutus, which has as large a brain as. and in some respects a higher type of dentitioa,] than, any existing lemur, and which eeemfl to be a progenitor of the monkeys. Did epa«4 permit, the curious Taeniodonta would doi notice.
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