790 



SCIENCE 



[N. S. Vol. XXXVII. No. 960 



In his last letter, Dr. Dall suggests a method 

 of reconciling the diilerences between teachers 

 and systematists by allowing the use of the 

 " text-book name " with the status of a ver- 

 nacular name, and a plus sign before it. I 

 adopted a somewhat similar compromise some 

 years ago, in a check list of American Ter- 

 tiary mammals, only I put the co mm only ac- 

 cepted name first, and the " correct " name 

 afterwards, enclosed in brackets and with an 

 equality sign before it. Now doubtless there 

 are specific differences between this and Dr. 

 Ball's discovery, but I claim that the genus is 

 the same, and that therefore, I am entitled ac- 

 cording to the law of priority of which he is 

 so able a defender, to that statue which he ex- 

 pects to receive from the grateful teachers. 

 Especially as I am sure my modification would 

 be more acceptable to them, and while I feel 

 less certain of his cordial approval, I don't see 

 what legitimate exception he can take to it. 



The vertebrate paleontologist is in some re- 

 spects almost free from the diiEculties in in- 

 terpreting and applying the laws of nomen- 

 clature that beset his zoological brother. The 

 literature with which he deals is mostly of 

 recent date, and reasonably cognizant of the 

 laws and decencies of nomenclature. There 

 are only a few cases in vertebrate paleontology 

 where there is any particular diiSculty in fix- 

 ing the type of a genus, the date of its pub- 

 lication or the species intended to be included 

 under it. 



His serious problem lies in the nomencla- 

 ture of species, the identification of type speci- 

 mens, and especially to know what to do with 

 the fragmentary and almost indeterminate 

 types of most of the older and many of the 

 newer species, in relation to more complete 

 specimens subsequently obtained. A quota- 

 tion from Professor Marsh may be apropos. 



A single tooth or vertebra may be the first 

 specimen brought to light in a new region and 

 thus become the sole representative of a supposed 

 new form. The next explorer may find more per- 

 fect fragments of the same or similar forms, and 

 add new names to the category. A third investi- 

 gator with better opportunities and more knowl- 

 edge may perhaps secure entire skulls or even 



skeletons from the same horizon, and thus lay a 

 sure foundation for a knowledge of the fauna.' 



The wording is curiously suggestive of Pro- 

 fessor Marsh's probable opinion of the activi- 

 ties of Leidy, Cope and himseK in the field of 

 American paleontology; but it is at all events 

 a suiEciently accurate description of the gen- 

 era] progress of the science. The earliest finds 

 in any newly explored formation are generally 

 fragments. They are new, they are of scien- 

 tific importance, they are distinct from forma 

 hitherto known, they ought to be described 

 and figured, and they ought to be named as a 

 matter of convenience in scientific discussion. 

 But they will undoubtedly make trouble later 

 for the systematist. The " next explorer " 

 must either " add new names to the cate- 

 gory " or identify one or more of his frag- 

 ments with the first described type. And if 

 his material comes from a different locality 

 such identifications may cause serious errors 

 in stratigraphic correlation. The third in- 

 vestigator may ignore the earlier types as too 

 incomplete for identification, or he may arbi- 

 trarily identify them with such of the species 

 secured by him as suits his convenience. 

 Either method will subject him to criticism 

 and be liable to mar the scientific results of 

 his investigations. 



It is a covenant universally accepted that a 

 new species is not to be described unless it can 

 be shown or inferred to be different from all 

 previously described species. But here it 

 simply can not be applied. The third investi- 

 gator may have at hand skulls and skeletons 

 of a dozen species all clearly distinct from one 

 another, yet any one of them may be cospecific 

 with the tooth or fragment on which an earlier 

 species was founded, and it is often absolutely 

 impossible to find in the type any characters 

 that are really valid evidence for referring to 

 it one rather than another of these later dis- 

 covered species. 



The difficulty in treating of these more or 

 less indeterminate species recurs again and 

 again in the literature of vertebrate paleontol- 

 ogy, causing endless confusion and error when 

 arbitrary identifications are subsequently 



'"The Value of Type Specimens," Am. Jour. 

 Sci., 1898, Vol. VI., p. 402. 



