36 
A Monograph of the genus Auliscus. By R, K. Greville, 
LL.D.,F.R.S.E.,&c. 
(Communicated by E. C. S. Eopee, P.L.S., &c., and read March 11th.) 
It is impossible to be engaged in the study of natural 
science at the present time^ and especially in the more prac- 
tical departments^, without being perpetually involved in the 
qu(Bstio vexata, What is a species ? Even in working out the 
following monograph of the small genus Auliscus^ I have 
found myself beset with difficulties; and without doubt 
some of my conclusions will be challenged by labourers in 
the same field, who hold (with perfect right) what they 
assume to be the most orthodox views. But who is to 
decide between conflicting opinions ? And so the question 
again recurs, What is a species ? It is singular that what 
appears at first sight to be so clear in theory, should be 
found practically in the direst confusion. Naturalists of the 
greatest reputation are not agreed on even the first step. 
Thus, Professor J. G. Agardh, in his ' Theoria Systematis 
Plantarum,^ after quoting various eminent naturalists, re- 
marks — " Ex his, quae breviter attulimus, satis, credo, 
apparet, tres nostrse setatis vel excellentissimos naturae inves- 
tigatores in ilia, quam proposuimus, qusestione dijudicanda, 
inter se dissentire. Schleidenius sola individua, Lindley 
species, Eriesius species et genera a natura vult constituta, 
majores omnes ordines ab arte inventos esse.^^ 
" A species, says Professor Walker-Arnott, in the Lin- 
nean sense of the word .... is formed by our Maker, as 
essentially distinct from all other species, as man is from the 
brute creation : ' Species tot numeramus, quot diversse 
formse in principio sunt creatse,'' Linn. It ought neither 
for convenience to be united with others, nor be split into 
several on account of newly detected diversities of form ; 
but the difficulty is to ascertain what is such a primitive 
or natural species, and how to characterise it so as to include 
those numerous varieties and individuals now existing on the 
surface of the globe which have sprung from it, but of which 
none may bear greater resemblance to the original or typical 
form than they now do to each other.'^^ This is sufficiently 
disheartening ; and Bentham, than whom a higher authority 
can scarcely be quoted, is not more encouraging. The 
species/' he remarks, in the ordinary traditional accepta- 
* * British Plora/ "Introduction." 
