The name of the genus being fixed, the species may be marked (Art. 257) by adding to it 'a single word taken at will from any quarter;' that is, it need not involve a description or any essential property of the plant, but may be a casual or arbitrary appellation. Thus the various species of _Hieracium_[44\4] are _Hieracium Alpinum_, _H. Halleri_, _H. Pilosella_, _H. dubium_, _H. murorum_, &c., where we see how different may be the kind of origin of the words. [Note 44\4: Hooker, _Fl. Scot._ 228.] Attempts have been made at various times to form the names of species from those of genera in some more symmetrical manner. But these have not been successful, nor are they likely to be so; and we shall venture to propound an axiom in condemnation of such names. APHORISM XVI. _Numerical names in Classification are bad; and the same may be said of other names of kinds, depending upon any fixed series of notes of order._ WITH regard to numerical names of kinds, of species for instance, the objections are of this nature. Besides that such names offer nothing for the imagination to take hold of, new discoveries will probably alter the {310} numeration, and make the names erroneous. Thus, if we call the species of a genus 1, 2, 3, a new species intermediate between 1 and 2, 2 and 3, &c. cannot be put in its place without damaging the numbers. The geological term _Trias_, lately introduced to designate the group consisting of the _three_ members (Bunter Sandstein, Muschelkalk, and Keuper) becomes improper if, as some geologists hold, two of these members cannot be separated. Objections resembling those which apply to numerical designations of species, apply to other cases of fixed series: for instance, when it has been proposed to mark the species by altering the termination of the genus. Thus Adanson[45\4], denoting a genus by the name _Fonna_ (_Lychnidea_), conceived he might mark five of its species by altering the last syllable, _Fonna_, _Fonna-e_, _Fonna-i_, _Fonna-o_, _Fonna-u_; then others by _Fonna-ba_, _Fonna-ka_, and so on. This would be liable to the same evils which have been noticed as belonging to the numerical method[46\4]. [Note 45\4: Pref. clxxvi.] [Note 46\4: In like manner the names assigned by Mr. Rickman to the successive of styles of Gothic architecture in England,--_Early English_, _Decorated_, and _Perpendicular_,--cannot be replaced by numerical designations, _First Pointed_, _Second Pointed_, _Third Pointed_. For--besides that he who first distinctly establishes classes has the right of naming them, and that Mr. Rickman's names are really appropriate and significant--these new names would confound all meaning of language. We should not be able to divide Early English, or Decorated, or Perpendicular into sub-styles;--for who could talk of _First Second Pointed_ and _Second Second Pointed_; and what should we call that pointed style--the _Transition_ from the Norman--which precedes the _First Pointed_?] APHORISM XVII.