April 23, 1897.] 



SCIENCE. 



637 



•described in the original paper. Students 

 of parasitic insects often rear numerous in- 

 dividuals from a single mother of a new 

 species, any one of which is naturally as 

 much like the tj^pe as those selected by the 

 author. Some of the individuals of such 

 broods are distributed to other workers and 

 museums as types. For a clear description 

 of a new species a paleobotanist may re- 

 quire as many individuals as there are 

 specimens selected for study, all of which 

 are regarded as types. Because of the 

 general imperfection of fossils, much of the 

 original material is usually accepted by pa- 

 leontologists as types, but when specimens 

 are figured, as is the general custom, it is 

 good practice to regard these alone as types. 

 The writer is not aware that any inverte- 

 brate paleontologist in America ever con- 

 siders 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 the multi- 

 plicity of types is generally 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 interpretation 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 spe- 

 cies is later found to contain diverse ele- 

 ments. 



The writer believes that it is possible to 

 harmonize all these difi"erent conceptions as 

 to what constitutes a type. The following 

 is, therefore, offered as an expression of in- 

 dividual opinion, in the hope that biologists 

 will, when necessary, emend the different 

 definitions here given or offer new ones, so 

 that a proper terminology in regard to 

 types may come into general use. 



KINDS OF TYPES. 



Type Material. — This includes all speci- 

 mens which have served as the basis for 

 published primary and supplementary de- 

 scriptions and figures. Mere lists of names 

 should not be regarded as based upon 

 ' type material ; ' neither should typical un- 

 described specimens of the original series 

 identified by the author of a new species, 

 nor the reared original duplicates of a 

 series out of which the type material was 

 selected, be sent out to collectors and 

 museums as types. There are, therefore, 

 two great groups of type material : primary 

 and supplementary tj'pes. These may be 

 defined as follows : 



Primary Types. — These are the described 

 or figured specimens of any new species. 

 There are three kinds of primary types : 

 holotype, cotype and paratype. To these 

 may be added a fourth, plastotype, includ- 

 ing all artificial reproductions moulded di- 

 rectly from some primary type. 



Suppleme7itary Types. — These consist of 

 the described or figured specimens used in 

 publication in extending or correcting 

 knowledge of a previously defined species. 

 For such type material the term hypotype 

 (7i2/po=under or sub, and typos=typ6) may 

 be used. For artificial reproductions 

 moulded directly from a supplementary 

 type, hypoplastotype may be useful. 



The collective term, ' type material,' 

 therefore includes all specimens used in 

 publications and upon which the entities 

 of natural science are founded. ' Primary 

 types ' include only the material of a new 

 species, while ' supplementary ' or ' hypo- 

 types ' are those specimens supplementing 

 knowledge of a previously defined species. 

 The various kinds of primary types may 

 be defined as follows : 



Holotype (/ioZos= whole or entire, and 

 typos=type). — A holotype in natural history 

 is a particular individual deliberately se- 

 lected by the author of a species, or it 



