INTRODUCTION. 
V 
naeus, is so vague and general in his specific characters, as often to leave us to 
mere conjecture as to the species which he designs; the characters of which 
he constitutes his specific distinctions being, in many instances, such as apply 
generally to a whole group, and, with some exceptions, to the greater part 
of the order. Of him in fact who consults the genus Testudo of the Systema 
Naturae , it may he said without exaggeration, in the words of Schoepff, 
“Inveniet enim nomina vaga, descriptiones plerasque mancas, ambiguas, in 
diversissima saepe quadrantes animalia, immo et diversissimis applicatas. 
Gmelin indeed acknowledges, “ Similitudinem structurae in generalibus, varie¬ 
tatem singularum specierum pro varia aetate, cognitionem plurium in variis vitae 
periodis imperfectam esse, et difficilem reddere testudinum diagnosin et mancam 
illarum historiam.” In this passage are contained the most striking causes of 
that uncertainty and vagueness which rendered the Systema Naturae so unsatis¬ 
factory an authority, as it regards these animals; still it must be granted that this 
great naturalist ascertained, with considerable accuracy, the characters which 
distinguish the marine, the lacustrine, and the terrestrial forms; and it is pro¬ 
bable that, had he been acquainted with a greater number of species, he would 
have acquired those accurate views of the relations and value of their characters, 
which would have constrained him to multiply his genera, and probably also 
to appreciate the real rank and importance of the whole group. 
There cannot be a higher practical attestation to the merits of this extraordi¬ 
nary man, than the fact, that even the most bigoted admirers of modern systems, 
who follow novelty for its own sake—no less than those more original and 
philosophical investigators of nature, who are obliged, by the very increase of 
their information, to acknowledge the deficiencies of his system—are constrained 
to adopt most of his groups, though they may assign to them a different grade 
in the scale. It is unpleasing to witness the paltry attempts which are every 
day made by the pygmies of science, to underrate and cavil at the views of that 
giant mind, whom they only affect to depreciate because they are unable to com¬ 
prehend him. It is not, however, to the servile herd of imitators, that this 
attempt to preach a sort of crusade against the merits and memory of Linnaeus 
is confined : some of the most gifted of our contemporaries, whose talents and 
acquirements give them a legitimate claim to more positive and independent 
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