476 EDWARD L. TROXELL 
from Daeodon (D. shoshonensis Cope), or the dinosaur Tyranno- 
saurus, which may be identical with Manospondylus (M. gigas 
Cope). Many such examples might be given showing where a 
more complete skeleton has usurped the taxonomic position of a 
type based on a mere fragment, thereby forcing the latter to fall 
into a group of historic relics, which merely mark the progress of 
our science. 
A new kind of type specimen.—lt is here suggested that we 
recognize this principle of substitution as a useful one, and we 
propose the name of protype (=for the proterotype) for such a 
supplanting type specimen. A protype should be based only on a 
very complete skull or skeleton. It is based on supplementary 
material, and as such is one of the forms of apotypes. In other 
words, a protype may be said to be a proxy, for it operates with 
full authority under a special designation. The material of a 
protype should, it would seem, be given a new name, preferably as 
a subspecies, for in such a humble position under the original pro- 
terotype it preserves the name of the older species replaced; it has 
the taxonomic advantage of linking the two together, and further- 
more, if it is later found that the new specimen is not identical with 
the older, the subspecies can be raised to the full rank of a species. 
Thus it is evident that a new species name should only be given, 
first, in the case of a protype, as just set forth, and second, to any 
specimen, fragmentary or perfect, which clearly possesses distin- 
guishing features or some unusual or unique morphologic character — 
that may be accentuated by its stratigraphic occurrence and that 
needs to be published and made widely known, thereby adding to 
the sum total of human knowledge. 
Making of species —Many naturalists have ventured an opinion 
as to what limit of variation should constitute the bounds of a 
species. This has, by common consent, been determined by the 
limits of interbreeding, where procreation is impossible or the 
offspring is sterile. In the natural state, it is interesting to note 
that, though the barrier is usually a physical or physiological one, 
yet it may be purely psychological, and as such may break down in 
captivity, giving rise to most unusual hybrids capable of repro- 
ducing their kind. 
