474 Mr. Blackwall oji the 



have a considerable degree of curvature, and taper gradually 

 to a fine point ; those of the lower row being stronger, more 

 closely set, and less curved. Inclined towards each other, the 

 two sets, in the performance of their functions, describe a series 

 of acute angles whose vertices are directed down the joint. 

 This important appendage constitutes a striking specific charac- 

 ter, which ought on no account to be omitted in descriptions 

 of Clubiona atrox. 



When the spider purposes to form a flocculus, it presses its 

 spinners against one of the glossy lines composing the founda- 

 tion of its snare, and emitting from them a small quantity of 

 liquid gum, attaches to it several fine threads, drawn out by ad- 

 vancing the abdomen a little, and kept distinct by extending 

 the mammulae laterally. The foot of one of the hind-legs is 

 then applied to the superior part of the upper tarsal joint of the 

 other hind-leg, a little above its articulation with the lower joint 

 of the tarsus, and the curious apparatus of spines, above de- 

 scribed, is brought immediately beneath the spinners at right 

 angles with the line of the abdomen. By a slight extension of 

 the joints of the hind-legs the apparatus is forced backwards 

 across the mammulae, the diverging extremities of which it 

 touches in its transit, and is restored to its former position by 

 a corresponding degree of contraction in the joints. In pro- 

 portion to the continuation of this process, (and it is not at all 

 unusual for the spider to pass its spiny apparatus across the 

 points of the mammulae several hundred times in rapid succes- 

 sion,) the inflected lines of the flocculus are found to be pro- 

 duced, the spider making room for them as they accumulate, 

 by elevating and at the same time advancing the abdomen in a 

 small degree, which it effiects by slightly extending the joints of 

 the third pair of legs, and contracting those of the two anterior 

 pair. As this operation is generally accomplished in the night, 



it 



