


1891.] Notes on Mesozoic Mammalia. 613 
senting a single type, led into other serious errors. This method, 
which belongs rather to metaphysics than to natural science, Prof. 
Osborn has again used in the present review, and with no better 
results. ; 
This long review purports to discuss my first and second papers 
on Cretaceous mammals. The first thing that strikes the careful 
reader is the title he gives to these papers. My own title was a 
simple one, “ Discovery of Cretaceous Mammalia,” and it is only 
fair to expect, in an elaborate review, that the title, at least, will be 
correctly quoted. Instead of this, Prof. Osborn has added ‘two 
other words, giving it a different meaning, but quoting it as mine: 
namely, “The Discovery of the Cretaceous Mammalia.” He 
read this review in no less than three different cities, and pub- 
lished an abstract elsewhere, yet apparently had no time to read 
my title of four words carefully enough to quote it correctly. A 
small matter, perhaps, but proof positive of careless work. 
The next point to be noticed is that my order Allotheria is 
rejected as not having been defined, and a later term, Multituber- 
culata, is adopted because it has been defined. This direct state- 
ment of Prof. Osborn is incorrect, as my order was defined when 
proposed in 1880 (Am. Jour. Sci., Vol. XX., p. 239). The cum- 
bersome term Multituberculata was not defined when proposed 
by Cope in 1884, but Prof. Osborn kindly attempted this in 1888. 
His definition, unfortunately, does not include some characteristic 
forms of the group, but takes in accurately the genus Mastodon, 
although this great Proboscidian can hardly be considered a 
Marsupial. 
By way of instruction, Prof. Osborn is good enough to indicate 
what he terms “ the main characters of the dentition of the Meso- 
zoic mammals in general, and some characters which enable us to 
distinguish between the teeth of mammals and those of reptiles 
and fishes.” This is a most promising statement, but loses some 
of its force when we find that it has not saved him from precisely 
these mistakes, either in his previous papers or in the present 
review, as I show later. 
_ He is scarcely more fortunate in his announcement of what he 
regards as the well-known characters of the teeth of one group, 
