By attention to this rule we may judge what expressions to select in cases where substantives are needed. I will take as an example the division of the mammalian animals into Orders. These Orders, {333} according to Cuvier, are _Bimanes_, _Quadrumanes_, _Carnassiers_, _Rongeurs_, _Edentés_, _Ruminants_, _Pachydermes_, _Cétacés_; and of these, _Bimanes_, _Quadrumanes_, _Rodents_, _Ruminants_, _Pachyderms_ are admissible as English substantives on the grounds just stated. _Cetaceous_ could not be used substantively; but _Cetacean_ in such a usage is sufficiently countenanced by such cases as we have mentioned, _patrician_, &c.; hence we adopt this form. We have no English word equivalent to the French _Carnassiers_: the English translator of Cuvier has not provided English words for his technical terms; but has formed a Latin word, _Carnaria_, to represent the French terms. From this we might readily form _Carnaries_; but it appears much better to take the Linnæan name _Feræ_ as our root, from which we may take _Ferine_, substantive as well as adjective; and hence we call this order _Ferines_. The word for which it is most difficult to provide a proper representation is _Edenté_, _Edentata_: for, as we have said, it would be very harsh to speak of the order as the _Edentates_; and if we were to abbreviate the word into _edent_, we should suggest a false analogy with _rodent_, for as _rodent_ is _quod rodit_, that which gnaws, _edent_ would be _quod edit_, that which eats. And even if we were to take _edent_ as a substantive, we could hardly use it as an adjective: we should still have to say, for example, the _edentate_ form of head. For these reasons it appears best to alter the form of the word, and to call the Order the _Edentals_, which is quite allowable, both as adjective and substantive. [An objection might be made to this term, both in its Latin, French and English form: namely, that the natural group to which it is applied includes many species, both existing and extinct, well provided with teeth. Thus the armadillo is remarkable for the number of its teeth; the megatherium, for their complex structure. But the analogy of scientific language readily permits us to fix, upon the word _edentata_, a special meaning, implying the absence of one particular kind of teeth, namely, incisive teeth. Linnæus called the equivalent order _Bruta_. We could not {334} apply in this case the term _Brutes_; for common language has already attached to the word a wider meaning, too fixedly for scientific use to trifle with it.] There are several other words in _ate_ about which there is the same difficulty in providing substantive forms. Are we to speak of _Vertebrates_? or would it not be better, in agreement with what has been said above, to call these _Vertebrals_, and the opposite class _Invertebrals_?