March 1, 1895.] 



SCIENCE. 



243 



and Crafogeomys are represented in the 

 United States; the former, with seven spe- 

 cies and five sub-species, scarcely extends 

 across our southern border ; the latter, 

 with seven species and one sub-species. 

 is mainly Mexican, one species, however, 

 ranging noi-thward over southeastern New 

 Mexico and northwestern Texas. Macro- 

 geomyif is known only Ironi Costa Rica; He- 

 terogeomi/K and Orthogroint/^ occupj' separate 

 areas in southern Mexico and Guatemala; 

 Pappogeoiinj.i, Plafi/geomi/i< and Zygogeomys 

 occur in central and western Mexico, the 

 latter l>eing known , only from a very re- 

 stricted area in the State of Michoacan. 



The chapters on the Morphologj' of the 

 Skull and the Dental Armature bring into 

 strong relief many jioints in relation to 

 changes of structure, due to age and growth, 

 which have heretofore been only lightly 

 touched upon, and es])eeially the influence 

 of the masseter muscle upon the general 

 shape of the skull in adult life. The facts 

 here presented may well be studied with 

 care and profit by students of not only the 

 mammals of to-day, but of the extmct forms 

 as well. The skull is considered not only 

 as a whole, l)ut its individual bones are 

 treated in detail, with cuts showing the 

 skull sectionized. and young skulls in com- 

 parison with old ones of the same species. 

 The memoir thus illustrates some of the best 

 work and the tendencies of the ' new school' 

 in recent mammalogy. In fact, no similar 

 group of mammals has before been treated 

 in such exhaustive detail, or fi-om a mor- 

 phological .standpoint, or with such admi- 

 rable profusion of illustration. 



J. A. Allkn. 

 ajibbicas sivsecm of 

 Natural Histoby, Xkw York. 



The Planet Earth. Richard A. Gregory, 

 16 mo, pp. 108. Iklacmillan & Co., New 

 York. Price 60 cents. 

 This little book is called 'An Astronomi- 



cjil Introduction to Geography.' In the 



preface the reader is promptly informed 

 that in class books on Astronomy and 

 Geography the suljject of the eartli con- 

 sidered as a planet is treated inadequately 

 and uuscientilicalty. The author expresses 

 his hope that his treatment, which, by in- 

 ference, is both adequate and scientific, may 

 be the means of reviving the ' Observa- 

 tional Astronomy of pre-telescopic times.' 

 Just why the telescope should be tabooed, 

 or wh}- it is less ' scientific ' than strings 

 with beads strung on them, does not clearly 

 appear. It is quite evident, however, that 

 the author wishes to restore what is some- 

 times called the ' historical ' method of 

 presentation and instruction, according to 

 which the student is expected to traverse 

 the \y,\i\\ along which mankind has slowly 

 toiled in order to reach conclusions which 

 in the present state of our knowledge are 

 often quickly attained by perfectly logical 

 processes. There is, also, generally involved 

 in tliis method, the erroneous assumption 

 that a student can, in the short time avail- 

 able for his training in science and scienti- 

 fic metliods, re-discover for himself all the 

 great facts and principles which are the 

 fruit of ages of intellectual activity, if 

 onl}' he has a few simple appliances at hand 

 and is started in the right direction. This 

 is a very large error, and it is not desii'able 

 to pursue it farther at this point. Admit- 

 ting, therefore, and no one will venture to 

 denj- this, that much can be learned by a 

 proper study of the apparent motions of the 

 heavenlj' bodies, and that young people 

 should be led to make such study before 

 finishing or even beginning their study of 

 the earth, as it is presented in the .so-called 

 unscientific ti-eatment in Astronomy and 

 Geogi-aphy, it is yet extremely doubtful if 

 the book now under consideration will Ije 

 of reiil value to them. 



The first chapter, which forms a consid- 

 erable jiart of the whole, is devoted to ' the 

 constellations.' The continued fixedness of 



