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The heart of the spider is of a spindle shape, furnished with valves. It 
sends off arterial branches through which the blood circulates. The last, but by 
no means the least important part of the structure of the spider, is the spinnerets. 
These organs are of great interest. They are placed at the extremity of the 
abdomen, clustered together, and consist of two, three, or four pairs, are jointed, 
and differ in form and length. In some they are cylindrical, the upper pair being 
very long and having a free motion; in others they are nearly equal in length, 
short and cylindrical, or conical ; while in others they are short and bent towards 
each other, and look much like a rosette. The sides of the cones are covered with 
hairs, and on the summits are a number of fine horny tubes, at first sight 
resembling hairs. These form continuations of the spinning vessels. Sometimes 
the lower portions of the sides of the cones are furnished with spinning tubes, the 
remainder being covered with hairs. Each tube consists of two parts, a thick 
basal portion and a thin terminal portion, from the orifice of which the substance 
of the fibre exudes. The number of these spinning tubes differs according to the 
species, sex, and age of the spider. 
In the garden spider there are*more than a 1000 to each nipple or spinneret. 
In others 400, 300, 100. These spinnerets contain a viscid fluid, a kind of elastic 
gum which becomes hardened by exposure to the air, and is expelled at the will of 
the spider. From this viscid fluid the web filaments are formed, and as the 
filaments from each spinneret are projected outwards they agglutinate together to 
form a perfect thread, and thus each thread is composed of at least 4,000, and 
sometimes 6,000 filaments. Itis affirmed that a filament isso slender as to require 
4,000,000 to make up a thread as thick as one of the hairs of a man’sbeard. Kirby 
and Spence also say that ‘‘ The holes in the spinnerets are so fine and so crowded 
together that there are 1,000 of them in the space covered by the point of a needle, 
These filaments unite about the tenth of an inch from the spinnerets to form the 
thread with which the webs are made.” The strength of the web varies greatly. 
The threads of some exotic species possess a far greater power of resistance than 
ours do. Travellers state that in some countries spiders’ webs are so strong as to 
arrest humming birds as a net would, and that a man only breaks them with 
difficulty. Dr. Livingstone says, ‘“‘In some parts of the country (Africa) there 
are great numbers of a large beautiful spotted spider, the webs of which are about 
a yard in diameter. The lines on which these webs are spun are suspended from 
one tree to another and are as thick as coarse thread. The fibres radiate from a 
central point where the spider waits for its prey. The webs are placed perpen- 
dicularly, and a common occurrence in walking is to get the face enveloped in them 
as a lady is ina veil, Another kind of spider lives in society and forms so great 
a collection of webs placed at every angle that the trunk of a tree surrounded by 
them cannot be seen. A piece of the hedge is often so hidden by the spider that 
the branches are invisible. Another (species) is seen on the walls in the inside of 
the huts among the Makolols in great abundance. It is round in shape, spotted, 
brown in colour, and the body half-an-inch in diameter. The spread of the legs is 
an inch andahalf, It makes a smooth spot for itself on the wall covered with 
