242 MR. O. THOMAS ON IHE WOED " TYPE." [Mar. 14, 



As to categorj' I. there is or ought to be no confusion whatever. 

 The one specimen, and that alone, is the " type," no matter how 

 many specimens the original collector may afterwards send home, 

 or the original author after\^•ards determine. 



In the case of category II., all the specimens on which the author 

 based his species, be they many or few (but no specimens received or 

 named afterwards), would be " co-types," there being then no single 

 " type " of the species at all, as all the co-types may be supposed 

 together to foi-m the type. 



In the case of category III., as the author has selected his type, 

 that, and that alone, would remain as such, but since the other speci- 

 mens mentioned or enumerated by him in the original description 

 are of unquestionably great value in a typical sense, they ought also 

 to have a name and might be called " para-types " (or side-types). 



Next, to meet the case of specimens collected afterwards at the 

 same place as the originals, and having thus at least a local claim 

 to authenticity, the word topo-type (or place-type) might be 

 suggested, but it should, so far as possible, be restricted to 

 specimens collected within, say, a few miles of the original typical 

 locality. 



In addition, it may be thought that specimens received from the 

 original locality after the first description is published, but verified 

 as belonging to his own species by the describer of it himself, 

 should have a peculiarname, and for such there might be suggested 

 the name " meta-type " (or after-type). As, however, we know 

 from experience that it is by no means impossible for the author 

 of a name to apply it wrongly, such meta-types would be of but 

 little more value than simple topo-types, especially if determined 

 long after the first description of the species. 



The following are, then, the definitions now suggested for the 

 diffex'ent terms : — 



A Type is a single specimen either unaccompanied by others at 

 the time of description, or else deliberately selected as such by the 

 author out of a series. 



A Go-tijpe is one of two or more specimens together forming 

 the basis of a species, no type having been selected. No species 

 would have both type and co-types, but either the former, or two 

 or more of the latter. 



A Para-type is a specimen belonging to the original series, but 

 not the type, in cases whei"e the author has himself selected a type. 

 It should, however, be one of the specimens mentioned or enume- 

 rated in the original description. 



A Topo-type is a specimen simply collected at the exact locality 

 where the original type was obtained. 



A Meta-type is a specimen received from the original locality 

 after the description has been published, but determined as be- 

 longing to his own species by the original describer himself. 



