re 
head, known as the cagwt, and the ‘thorax 
fused together. It constitutes the anterior 
great division of the spider. To this part are 
attached the legs, which are eight in number. 
Some writers refer to the upper part of the 
cephalo-thorax as the sfzeld. The caput 
usually has the appearance of a more or less 
raised portion forced, as a wedge, into the 
anterior portion of the thorax. 
(2) Eves. These are placed on the anterior of 
upper surface of the caput, and in all British 
species are either six or eight in number. They 
are simple, usually of a dark colour, although 
in many cases they have a beautiful pearly 
appearance, other tints being occasionally 
found. The arrangement of the eyes is of the 
greatest importance in classification, consti- 
tuting a character for the formation of families 
and genera. Their comparative size, and very 
slight difference of position, are usually re- 
garded as specific characters. The position of 
the eyes on the caput is also important, the 
following terms being employed in describing 
the parts concerned :—Ociularv-area, the space 
bounded by the eyes; Clypeus, the tract ex- 
tending from the anterior eyes to the lower 
margin of the caput ; Aaczal-space, the ocular 
area and clypeus combined. 
(3) Lecs. As already stated, these are eight in 
number, and as far as British species are 
concerned, invariably consist of seven joints, 
which are named as follows, beginning from 
the body :—(a) extngwinal, (b) coxal, (c) 
femoral, (a) genwal, (e) tzébial, (f) metatarsal, 
(g) ¢arsal. The exinguinal, coxal, and genual 
joints are usually much shorter than the re- 
mainder. The tarsus terminates with two or 
three claws, usually pectinated, and beneath 
this portion is sometimes placed a number of 
closely-set hairs, known as scopzla. On the 
metatarsal joints of the fourth pair of legs, in a 
few species, a row of short curved bristles will 
be noticed. These constitute the calamistvum, 
which is used in the preparation of a peculiar 
flocculent web secreted by a special spinning 
organ, always present in such spiders. The 
relative length of the legs is useful as a generic 
character, the formula 4 1 3 2, for example, 
indicates that the fourth leg is the longest, the 
first coming next in order of length, and the 
second being the shortest. If a leg is acci- 
dentally lost, another, but smaller, limb is 
produced in its place. 
Fatces. These are two strong organs placed 
below and on the front part of the cephalo- 
thorax. They each terminate in a sharp fang, 
capable of more or less motion, and containing 
a minute channel, through which a rapid 
poison is forced from the fang. 
194 SCIENCE-GOS SIP. 
consists of drawings taken from Zegenaria derhanei, (5) Maxittar. These are strong plates situated 
selected as being a well-known and fairly typical spider. behind the falces, and with the /adzawm—a 
(1) CEPHALO-THORAX. This really consists of the small plate lying between the maxillae—they 
form theexternal parts of the mouth. The 
maxillae are important as generic characters, 
as is the labium. 
(6) PALri. These are the two five-jointed limbs 
springing from ‘the maxillae. In the female 
they are sometimes used as organs of locomo- 
tion. In the male, however, they are highly 
developed, and employed by the animal for 
the purpose of transferring the spermal fluid, 
either directly or indirectly, from its own 
genital aperture to that of the female. The 
terminal joint, known as the digital joint, is 
often very highly developed, consisting of 
variously shaped corneous receptacles and 
ducts. The next two joints are known as the 
radial and cubital respectively, and with the 
digital joint, are most reliable specific characters. 
The remaining joints are termed humeral 
and axillary. 
(7) ABDOMEN. This is the posterior great 
division of the body, and is usually more or 
less of an oval shape, although subject to great 
variation in form. The upper surface is 
generally marked to a greater or less extent, 
and is commonly clothed with hairs. On the 
underside, near the anterior portion of both 
sexes, is the genital aperture. The female 
organ is rather prominent, and of the greatest 
importance as a specific character. Its 
development as a distinct orifice is a sure 
indication of maturity. The male aperture is 
similarly placed, but is very small and 
difficult to distinguish. On each side of the 
genital area are the external, openings of the 
respiratory apparatus. In most species they 
are only two in number, but in a few genera 
there is an extra pair placed nearer the 
posterior extremity. The abdomen terminates 
in the spinners, the office of which is to 
secrete the web. In the case of spiders 
having calamistra, an extra spinning organ is 
present. This secretes a peculiar web, which 
is formed into a flocculent layer surrounding 
the animal’s retreat. The cross lines of 
many webs, that of dAvraneus (Epeira) 
diademata for example, are studded with 
viscid globules for the better retention of the 
spider’s prey. These globules are not placed 
sepaiately in position by the spider, but are 
DESCRIPTION OF FIG. 2, PAGE 195. 
a, Female; 6, @ side view (legs truncated) ; 
c, Eyes, from above ; @, Eyes and falces from in front ; 
e, Thorax (underside); /, Abdomen (underside) ; 
e, Leg; 2, Male palpus (profile); 7, Female genital 
aperture ; 7, Male palpus from underneath. 
Joints of Leg.—t, Exinguinal; 2, Coxal; 3, 
Femoral; 4, Genual; 5, Tibial; 6, Metatarsal ; 7, 
Tarsal. 
Joints of Palpus.—1, Axillary; 2, Humeral; 3, 
Cubital ; 4, Radial; 5, Palpal organs; 6, Digital. 
