1002 The American Naturalist. [November 
have often been observed. They capture the species of insects 
and spiders which they store for the use of their young by sting- 
ing them in the nervous ganglia in such a way as to paralyze 
without killing them, thus preserving them alive for many months. 
The construction of webs by spiders furnishes an excellent 
illustration of the progressive development of a capacity for 
mechanical construction. The inferior forms construct loose 
nets in the grass. Another type adds to this a funnel-shaped 
retreat, in which they lie in wait. A higher form suspends a tri- 
angular net between the branches of a bush, while the perfection 
of the art is reached by such Epeiride as spin a complete disc 
composed of many triangular segments, which often contains a 
staircase from the centre, arranged for their ready escape from an 
enemy. At some early period in the history of the spiders an 
intelligent perception of the utility of a web in the capture of 
prey must have been attained. The habit of making the web has 
become ingrained or instinctive, and has by use absorbed the 
faculties of the species. Accident has perhaps led to the habits 
of constructing them differently with relation to the environment, 
such as the surface of the ground, etc. The triangular form is 
the simplest possible device for a suspended web, while the dis- 
coidal web is constructed by a simple repetition of the same 
device. This probably means merely increased capacity for web- 
construction ; that is, increased secretion of web-substance, and 
increased nervous activity, both the result of use. 
The intelligence displayed by the higher animals in the capture 
of prey is well known. I once had a tame raccoon which was 
fastened by a chain of moderate length in a stable. He fre- 
quently attempted to catch the chickens that entered the stable, 
but was prevented by the shortness of his chain. But he adopted 
a device which was successful. He collected the remains of his 
meals within the circle of which his chain formed the radius. He 
then pretended to go to sleep at a point near the the centre of the 
circle, while he slyly watched the birds. The latter approached, 
and, becoming confident, proceeded to peck at the fragments. 
The raccoon then easily pounced upon and caught them. In 
the pursuit of their prey dogs, as is well known, display much 
