June 21, 1907] 



SCIENCE 



971 



first species mentioned would be likely to in- 

 troduce confusion. 



When genera are based on recent species it 

 may be assumed that, as a rule, no one species 

 is more obscure than another, so that, ceteris 

 paribus, there is no objection to taking as 

 genotype the first mentioned. Indeed the first 

 mentioned is in most cases likely to be .the 

 best known, although every one is aware that 

 it is not so in all cases. But when genera are 

 based mainly or entirely on fossils there is a 

 great difference between the values of the dif- 

 ferent species. The common-sense thing to 

 do in such a case is to select the most com- 

 pletely preserved and best-known species as 

 genotype. 



If now one considers the general action of 

 previous revisers in dealing with paleontolog- 

 ical material, one notes a ' general tendency 

 either to select as genotypes, or at all events 

 to regard as representative, those species which 

 are the least obscure. In other words, the 

 historical development of the science has re- 

 sulted in the common-sense method of inter- 

 preting genera by their best known species. 

 To leave the selection to an arbitrary rule 

 that is as likely as not to fix on an obscure 

 fragment would in itself be contrary to com- 

 mon sense; but the first species method now 

 proposed not merely ignores these important 

 factors of clearness and familiarity, but actu- 

 ally tends in the case of fossils towards the 

 greatest obscurity. For this reason, many 

 new species established by paleontologists have 

 been introduced in monographs or papers deal- 

 ing with series of fossils from various hori- 

 zons; and it has generally been the custom of 

 paleontologists, in discussing the species under 

 review, to follow a stratigraphical order, be- 

 ginning with the oldest rock. Consequently, 

 when a paleontologist founds a new genus, the 

 first species that he mentions is generally the 

 oldest, and for this very reason it is generally 

 - also the most obscure. In many cases then 

 the fijst species rule would lead to the in- 

 evitable selection of the most obscure species 

 as the type of a genus. A rule of which this 

 can be said may work with mathematical ex- 

 actness and automatic precision, but its final 

 result must be to introduce, or rather to force. 



into zoological nomenclature fresh elements 

 of uncertainty and change. 



F. A. Bather 

 London, S. W., England, 

 April 29, 1907 



THE GREAT INFERIOR TUSKED MASTODON OF THE 

 LOUP FORK MIOCENE 



In 1882 I discovered a jaw of this mastodon 

 on the Sappy, in Decatur County, while in the 

 employ of the Museum of Comparative 

 Zoology at Cambridge. A single jaw was 

 present measuring four feet to the end of 

 the tusk. Last year while on an expedition 

 for the Royal Museum of Munich in the same 

 beds on the Prairie Dog, I collected a very 

 perfect set, without the tusks; length of the 

 preserved jaws two and a half feet, height at 

 condyles fourteen inches, height of grinding 

 surface of the single last molar nine and a 

 half inches. Last season my son was so 

 fortunate as to discover in Scott County, near 

 the Gove County line, a very complete and 

 well-preserved set of lower jaws of a huge 

 specimen so different in several respects from 

 the other two mentioned, a separate form may 

 be represented. The peculiarity lies in the 

 low condyle that is only thirteen and a half 

 inches high, and in the great depression of the 

 rostrum, thirteen inches lower than the teeth 

 at its distal end. The length of the jaws are 

 four feet and one inch long. The distance 

 between the condyle and distal end of rostrum 

 or beak, four feet three and a half inches. 

 But one well-preserved molar, the last, in each 

 jaw their greatest height is ten inches; height 

 of crown two and a half inches, length nine 

 and a half inches, width three inches, distance 

 between the raolars four inches. This is the 

 largest specimen in my experience ever taken 

 from the Loup Fork Miocene beds of Kansas, 

 and point to an animal of large proportions. 



In this connection I would like to put on 

 record the description of the largest tusk of 

 Elephas colurnbi, or the great Columbian 

 mammoth, of which such a fine example is 

 now mounted in the American Museum, New 

 York City. I discovered this tusk with a lot 

 of teeth ; several of them are now preserved in 

 the State University Museum of Kansas and 



