io8o The American Naturalist. [December, 
ual bones or teeth of animals which subsequent discoveries have 
shown to belong to a single species. It is also probable that 
among fossil plants species have been made from pieces of stems, 
or from leaves, which more abundant material will show to be 
portions of but one. Species are not unknown that have been made 
upon the single arm of a single starfish in an unperfect state of 
preservation ; upon a fragment of a coral ; the compressed or 
distorted body of a crinoid ; the obscure internal cast of a bivalve ; 
or the head, tail, or spine of a crustacean. So far has the passion 
for genus and species making been carried, that inorganic mark- 
ings, " a single row of tracks," mud splashes, wave marks, and rill 
marks have been described : to say nothing of the scores of mol- 
lusk trails, worm trails, or worm burrows that have so long done 
duty as Algae. We are glad to see, in some quarters at least, a 
reaction from this excessive species making, though in other 
quarters the name coining still goes on. 
Perhaps one cause of the excessive multiplication of species in 
palaeontology is the refusal for so many years to recognize the 
fact that the same species may have existed in two distinct areas, 
or throughout two distinct epochs. As among certain botanists 
and zoologists the presence of the same species in two widely 
separated countries was, and is, considered sufficient cause to 
make two species, so the occurrence of identically the same 
forms, as far as our specimens can tell us, in two geologic hori- 
zons, or in two distinct localities, is considered prima facia evi- 
dence that we are dealing with two distinct species. Even in 
one of the latest monographs published by the U. S. Geological 
Survey (Vol. XIV.) we observe an inorganic marking (as it 
appears to, us), masquerading under the name of a sea-weed ; and 
under a new name, too, because its brother rill mark existed some 
geological ages prior to its own oncoming formations. So, too, 
we see species of corals, of shells, of cephalopods, of crustaceans 
and others bearing distinct names because one lived in the Cin- 
cinnati, and another lived in the Trenton period ; or because one 
lived in the ocean that covered New York, and the other that of 
