4. But wherever we may draw the line between the proper use of English and Latin terms in descriptive phraseology, we shall find it advisable to borrow almost all other technical terms from the learned languages. We have seen this in considering the new terms introduced into various sciences in virtue of our Ninth Maxim. We may add, as further examples, the names of the various animals of which a knowledge has been acquired from the remains of them which exist in various strata, and which have been reconstructed by Cuvier and his successors. Such are the _Palæotherium_, the _Anoplotherium_, the _Megatherium_, the _Dinotherium_, the _Chirotherium_, the _Megalichthys_, the _Mastodon_, the _Ichthyosaurus_, the _Plesiosaurus_, the _Pterodactylus_. To these others are every year added; as, for instance, very recently, the _Toxodon_, _Zeuglodon_, and _Phascolotherium_ of Mr. Owen, and the _Thylacotherium_ of M. Valenciennes. Still more recently the terms _Glyptodon_, _Mylodon_, _Dicynodon_, _Paloplotherium_, _Rhynchosaurus_, have been added by Mr. Owen to designate fossil animals newly determined by him. {324} The names of species, as well as of genera, are thus formed from the Greek: as the Plesiosaurus _dolichodeirus_ (long-necked), Ichthyosaurus _platyodon_ (broad-toothed), the Irish elk, termed Cervus _megaceros_ (large-horned). But the descriptive specific names are also taken from the Latin, as Plesiosaurus _brevirostris_, _longirostris_, _crassirostris_; besides which there are arbitrary specific names, which we do not here consider. These names being all constructed at a period when naturalists were familiar with an artificial system, the standard language of which is Latin, have not been taken from modern language. But the names of living animals, and even of their classes, long ago formed in the common language of men, have been in part adopted in the systems of naturalists, agreeably to Aphorism Third. Hence the language of systems in natural history is mixed of ancient and modern languages. Thus Cuvier's divisions of the vertebrated animals are _Mammifères_ (Latin), _Oiseaux_, _Reptiles_, _Poissons_; _Bimanes_, _Quadrumanes_, _Carnassières_, _Rongeurs_, _Pachydermes_ (Greek), _Ruminans_ (Latin), _Cétacés_ (Latin). In the subordinate divisions the distribution being more novel, the names are less idiomatic: thus the kinds of Reptiles are _Cheloniens_, _Sauriens_, _Ophidiens_, _Batraciens_, all which are of Greek origin. In like manner. Fish are divided into _Chondropterygiens_, _Malacopterygiens_, _Acanthopterygiens_. The unvertebrated animals are _Mollusques_, _Animaux articulés_, and _Animaux rayonnés_; and the Mollusques are divided into six classes, chiefly according to the position or form of their foot; namely, _Cephalopodes_, _Pteropodes_, _Gasteropodes_, _Acephales_, _Brachiopodes_, _Cirrhopodes_.