282 ON THE NETS OF GEOMETRIC SPIDERS. 
appropriation, whether the radius be in the plane of 
the snare, or whether it be withdrawn from that 
plane, as is frequently the case, imparts an unfinished 
appearance to the net, as it prevents the spider from 
giving her viscid line a spiral form, though this is 
sometimes attempted with a greater or less degree 
of success. No sooner does the spider arrive at one 
of the radii adjacent to that in connexion with her 
cell, than she returns, traversing the framework of 
her snare till she arrives at the proximate radius on 
the opposite side, when she again retraces her steps, 
and, thus oscillating between the two, spins a num- 
ber of curved, viscid lines, or arcs of circles, diminish- 
ing in length from the circumference of the net 
towards the centre. Dr. Lister, who has figured 
and described this species in his treatise ‘ De Araneis,’ 
fig. x. pp. 47 & 48, was well acquainted with this 
peculiarity, so common in the structure of its snare ; 
but be has fallen into the error of supposing that 
it occurs invariably, as appears from the following 
passage, cited from his work :—‘ Rete amplum & 
elegantissimum tendit: illud autem in eo perpetuum 
& singulare est, nimirim é radiis unicum maculis 
utrinque nudari, idque @ centro reticuli ad ejus 
usque circumferentiam; qui feré ad aliquam in pa- 
riete rimulam aut alibi, ubi animal tuto totum diem 
latet, porrigitur: atque hic radius ei velut scala est, 
per quem ascendat descendatque.” 
The learned authors of the ‘Introduction to En- 
