18 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 
has so admirably expressed as above, will at least be preferred by those 
who set as much store upon the habits and functions of the creatures as 
upon their forms. The latter indeed will not be undervalued by a wise 
and careful student; but the systematists and anatomists will doubtless 
bear with those who would fain keep natural history from swinging too 
far away from the paths which earlier naturalists trod, and which so 
thoroughly traversed the life history of created things. 
A general classification based upon the spider’s behavior, especially in 
relation to its chief function, has the advantage that it compels attention 
to the creature’s habit without at all neglecting its structure. It 
The Clas- is not claimed that this classification is without objections. There 
sification ; : a : : ; 
Justified. 2" indeed, some incongruities, more or less serious, which will 
appear hereafter. But until these interesting animals shall have 
received from naturalists that attention which their character and impor- 
tance in nature justify, and which will enable some future arachnologist to 
show us a better way, we shall, perhaps, be best repaid by accepting this 
general grouping of the great families of the spider fauna. At least it is 
that which best serves my own purposes in the special lines marked out 
for this treatise. 
Students who are interested in a more thorough consideration of this 
point will find the objections to the above system well stated, and a classi- 
fication proposed based more upon anatomical structure, by Dr. Philip 
Bertkau, of Bonn. A very satisfactory answer to these objections has 
been published by Prof. Tamarlan Thorell, M. D.,2 who adheres substan- 
tially to his former system but, confessing his indebtedness to Prof. Bert- 
kau for certain modifications, proposes a rearrangement which, he thinks, 
answers to our present knowledge of this order, as follows :— 
Orpvo ARANER. 
Susorpo I. TrerRaAPNEUMONES. 
Tribus I. Territelarie. 
Suporvo II. Dipneumones. 
Tribus II. Tubitelariz. 
Ecribellatee, Cribellatee, 
Tribus III. Retitelariz. 
Tribus IV. Orbitelarie. 
Cribellate. Ecribellatze. 
Tribus V. Laterigrade. Tribus VI. Citigrade. Tribus VII. Saltigrade. 
The scheme embraces European families for the most part, but includes 
a few exotic ones. 
1See especially his “Versuch einer natiirlichen Anordnung der Spinnen,” in Archiy far 
Naturgeschichte, xliv., i., page 351, sq., 1878; and his treatise “Ueber das Cribellum und Cala- 
mistrum, Ein Beitrag zur Histiologie, Biologie, und Systematik der Spinnen,” ibid, xlyiii,, i. 
page 316, et seq., 1882. ’ 
2 Annals and Magazine Nat. Hist., Apl., 1886. “On Dr. Bertkau’s Classification of the 
Order Aranez or Spiders,’ by Prof. T, Thorell. 
