Januaet 1, 1897.] 



SCIENCE. 



29 



epochs originated high up in the northern hemis- 

 phere, if not, indeed, in the neighborhood of 

 the pole itself." 



In some instances Mr. Lydekker calls par- 

 ticular attention to the widely different cli- 

 matic conditions prevailing in Tertiary times 

 from those of the same areas in our times, with 

 consequent dissimilarities in past and present 

 faunas ; in other cases he assumes that the 

 boundaries of existing faunas coincide essen- 

 tially with those of the antecedent fossil faunas 

 of the same area. Thus while explaining the 

 great differences in the past and present life of 

 the Arctic region on the ground of changes of 

 climate, he would have us believe that the 

 Sonoran region has maintained essentially its 

 present boundaries since the days when it was 

 inhabited by the remarkable extinct mammals 

 known as Creodont Carnivora, Oreodont Un- 

 gulates, Protoceras, Camels, Titanotheriums, 

 Coryphodons and others, all of which he re- 

 gards as of Sonoran origin. While of much 

 interest to know what types originated in this 

 geographic area, does anyone imagine that its 

 climate, when these extraordinary animals 

 lived there, was the same as to-day ? 



But all this is preliminary. Coming to the 

 real subject of the book Mr. Lydekker parcels 

 off the globe into the following primary and 

 secondary divisions : 



I. Notogseic Eealm. — 1. Australian Region. 



2. Polynesian Eegion. 



3. Hawaiian Eegion. 



4. Austro-Malayan Eegion. 

 n. Neogseic Eealm. — Neotropical Eegion. 



III. Arctogseic Eealm. — 1. Malagasy Eegion. 



2. Ethiopian Eegion. 



3. Oriental Eegion. 



4. Holarctic Eegion. 



5. Sonoran Eegion. 



To discuss this scheme with the fullness its im- 

 portance deserves would require far too much 

 space for the limits of the present review. The 

 primary regions, or ' realms, ' may be passed 

 without comment, inasmuch as few writers agree 

 on their numbers or boundaries ; and little will 

 be said of the paleontological side of the book 

 or of the facts of present distribution outside of 

 the Americas. 



Mr. Lydekker accords to South America the 



high distinction of primary rank, making it one 

 of the three great ' realms ' into which he divides 

 the whole world. But he fails to see in its 

 diversified faunas more than a single division of 

 secondary rank — the ' Neotropical region ' — 

 whose boundaries he conceives to be coincident 

 with those of the ' Neogseic realm ;' and it is not 

 until we come to divisions of the third rank, or 

 ' sub-regions, ' that he finds it necessary to take 

 into account the widely different faunas that 

 characterize the tropical forests, the grassy 

 pampas and the lofty Andes. This seems scant 

 justice, particularly by contrast with North 

 America, where three full 'regions' are admitted. 

 The number of Neotropical ' sub-regions ' re- 

 cognized is four, two of which — the Mexican 

 and the Antillean — are northern outliers, leav- 

 ing only two for the whole continent of South 

 America. Of these, the first, or ' Brazilian sub- 

 region,' "is essentially an area of dense tropical 

 forests, locally interspersed with open pastures 

 or 'campos.' The second is the Chilian sub- 

 region, comprising Chili, Argentina proper, 

 Uruguay, Patagonia and such portions of Peru 

 and Bolivia as are not included in the preceding. 

 It is chiefly an area of open plains and pampas, 

 although including the high Andes. ' ' 



If it could be assumed that Mr. Lydekker was 

 unacquainted with the mammal faunas of South 

 America, such a classification might be attri- 

 buted to an imperfect knowledge of the facts, 

 but his own enumeration of the characteristic 

 genera and families of the difierent areas pre- 

 cludes this view and shows that the difQculty is 

 mainly one of interpretation. 



In speaking of the Mexican extension of the 

 Tropical fauna, Mr. Lydekker makes the shock- 

 ing statement: "Dr. Hart Merriam has pro- 

 posed to unite Central America with the West 

 Indies to form a separate zoological region — the 

 Tropical — of equal rank with the Sonoran ; but, 

 however much may be urged in favor of this 

 view, the multiplication of regions is much to 

 be deprecated. " It is hard to understand how 

 any contortion of the imagination could give 

 birth to such an overwhelming misconception. 

 As a matter of fact, I simply remarked, after 

 defining the Sonoran region, that the lowlands 

 of Mexico, Central America and the West In- 

 dies belong to the American Tropical region — 



