ARTICULATA. 127 
the former by a small peduncle. The mandibles are strong, they move 
vertically, or to some extent horizontally, and they have a terminal movable 
curved nail or tooth, which has a pore near the point through which a 
poisonous fluid escapes. The mandibles of the male are generally larger 
than in the female, although the individuals of the latter sex are usually 
the largest. The palpi have five articulations, and are attached to the 
maxille or jaws. They are pediform, simple, and ending with a nail in the 
female, and variously shaped in the male. The maxillee vary much in 
shape, and afford good characters in classification. Between the maxille is 
the labium or under lip. The feet are of the same shape, but differ in length 
and thickness. They are usually terminated by a pair of serrated nails. 
There are six or eight eyes, but generally the latter number, and they are 
variously grouped in the different genera. The abdomen is usually soft, 
and sometimes very large. The generative organs are situated at its 
base beneath; it contains two or four spiracles, and towards the extremity 
are the vent, and spinnerets connected with the organs which secrete the 
silk. 
The effect of the poison of spiders has been much exaggerated, although 
under certain circumstances it may be serious. Walcknaer, a volumi- 
nous writer upon these animals, states that he has caused himself to be 
bitten by various species, but no ill effects resulted. 
Each spiniferet of a spider contains a multitude of pores which, in some 
species, amount to more than a thousand, so that the compound thread from 
four spinnerets may contain four thousand strands. It has been suggested, 
that as the strength of a rope is increased by being composed of many 
separate strands, the strength of the cord of a spider is secured in the same 
manner; but this is an error. The strands of a rope increase its strength 
because the ends of the separate short fibres are thereby better secured ; but 
the silk of the spider, being a uniform fibre, cannot be compared with a 
compound rope, and at best it is generally comparatively weak. The silk 
being in a liquid state within the body, and much being required in a short 
time (as when the spider descends by its thread), the extreme tenuity of the 
strands enables them to harden almost instantly by contact with the air. 
Newly born spiders are capable of spinning, and Leuwenhoeck has calculated 
that it would require four millions of the strands of one of them to form a 
thread as thick as a hair of his beard. 
Some spiders shoot out long lines of silk, which have sufticient buoyancy 
to serve them as balloons for transporting themselves through the air. In 
the autumn, these gossamers are abundant in the air and on the ground, 
and they may be frequently seen floating in the breeze with a spider 
attached. Thus an individual has been observed coming across the River 
Susquehanna upwards of three hundred feet above the water towards a cliff 
of that height. 
The webs of spiders are made according to various patterns. Some are 
closely woven into a funnel into which the spider retreats, and opening 
externally into a wide surface. The tube of the funnel sometimes extends 
into a hole in the earth, or other material. Among the webs stretched to 
331 
