8 INTRODUCTION. 



any individual of the original series, if more than one specimen was examined by the 

 describer. In this there was little cause for confusion, liut more recently it has been 

 applied to any individual from the collection of the original author, obtained no 

 matter how much later, and often not even determined by him as belonging to his 

 species. Of late a still further cause of confusion has been introduced by certain 

 authors who, obtaining specimens from the typical locality, have spoken of them as 

 "typical specimens," a method of reference which, although due to a praiseworthy 

 regard for geographical exactness, is yet certainly liable to give rise to inconvenience 

 and confusion. 



The late Dr. G. Brown Goode, in a circular letter to curators in the 

 U. S. National Museum, dated Jttly i, 1893, wrote that — 



By a type is meant a specimen which has been used by the author of a systematic 

 paper as the basis of detailed study, and as the foundation of a specific name. In 

 cases where a considerable number of specimens has been used it is desirable to 

 separate one or more as being primar}' types, while the other specimens, which may 

 have been used in the same study for the purpose of comparison, may be regarded 

 as collateral types. 



These citations show clearly that a type is not always restricted to a 

 single specimen selected by an author, but also applies to several or 

 even to all the specimens contained in the original lot. Moreover, the 

 word type has been applied to specimens sent out b}' the atithor of a 

 species, but not used in the original description. Sttidents of parasitic 

 insects often rear numerous individuals from a single mother of a new 

 species, any one of which is naturally as nuich like the type as those 

 selected by the atithor. Some of the individuals of such broods are dis- 

 tributed to other workers and museinns as types. For a clear descrip- 

 tion of a new species a paleobotanist may require as many individuals as 

 there are specimens selected for stud}-, all of which are regarded as 

 types. Because of the general imperfection of fossils, nutch of the orig- 

 inal material is tisualh' acccepted by paleontologists as types; but when 

 specimens are figured, as is generally the custom, it is good practice to 

 regard these alone as types. The writer is not aware that any inverte- 

 brate paleontologist in America tuttil recently considered a species to be 

 based upon a single specimen if others are present at the time of original 

 publication. It is doubtful if many species, living or extinct, can be 

 defined from a single individual; hence a nutltiplicity of types is gener- 

 ally a necessity. In birds and mammals, where the sexes usually exhibit 

 marked differences, there are seasonal modifications, a bony skeleton, 

 geographical and individual variation, and stages of growth, and all 

 these parts and variations require material for the proper and final inter- 

 pretation of species. The practice of selecting a single example as the 

 type, however, has its advantages, since all doubt is thus removed when 

 a new species is later found to contain diverse elements. 



The writer and others belie\'e that terms are necessary to distingtiish 

 the various kinds of type .specimens. This is .seen by the continually 



