62 Chapman, What are Type Specimens ? [vol'xxix. 



however, be one of the specimens mentioned or enumerated 

 in the original description." 



" A paratype may be subsequently selected as a holotype 

 when it proves to be a new species and is not the species to 

 which it was originally referred." — Schuchert. 



Supplementary Types. 



Plesiotype (Cossmann, 1904). — "An individual [of a de- 

 scribed form], whether from the same locality or another 

 deposit, which one compares with a species and for which one 

 gives a new description and a new figure, is a plesioty]ie of 

 that species." 



Neotype (Cossmann, 1904). — " Neotype for the specimen 

 afterwards taken as the type of a species when the original 

 type (holotype) has been destroyed or has disappeared, with the 

 necessary guaranty of its authenticity ; but it seems indispensable 

 that the new specimen should come from the same locality and 

 exact horizon." 



Tectotype (Chapman, 1912). — A tectotype is a specimen, 

 fragmentary or otherwise, which is selected to elucidate the 

 microscopic structure, internal or external, of a species or 

 genus. It may consist, for example, of a tooth-section, a 

 shell-flake, a sliced foraminifer, or a preparation from a fossil 

 leaf. A tectotype may be associated, in the case of a species, 

 with the original types (tectoparatype), or with subsequently 

 described specimens (tectoplesiotype). 



Typical Specimens (Icotypes). 



Topotype (Thomas). — " A specimen collected at the exact 

 locality or within a few miles of the place where the original 

 type of a species was obtained." 



" In paLxontology, it is further demanded that the to])otype 

 should come not only from the exact locality but also from 

 the identical stratum that furnished the species." — Schuchert. 



Houurotype (Homotype, Walsingham and Durrant ; re- 

 defined by Schuchert). — " A homreotype is any sui)i)lementary 

 specimen that has been carefully compared with the primary 

 types by a worker of recognized standing in the class of 

 organisms to which the material belongs." 



Ideotype (Buckman). — Specimens " from any place except 

 the original locality named by an author of a species after 

 ))ul)lication. When similar specimens are liom the original 

 locality they are nietatypes." 



Reproduction of Type Specimens. 



Plastofype (Schuchert). — "Specimens in jilaster of Paris, 

 sulphur, or lead castings, gutta-percha squeezes or electro- 

 types " direct from the originals. Models not inchulcd. 



