Savory - Arachnida 1977

162 III. PROLES ARACHNES
is found in South Africa and Capomina in South America. From South
America and some of the adjacent islands comes the genus Nops,
peculiar in the possession of two eyes. The Symphytognathidae were
founded on the remarkable spider 5)mph)'tognatha globosa, described
by Hickman from Tasmania in 1931. In this spider the pedipalp of
the female consists solely of the coxal segment with its gnathobase, a
reduced condition almost without parallel in Arachnida.
Among the Dipneumonatae the families of the Sicarioidea include
two which have six eyes, the Dysderidae and Oonopidae. These are
relatively primitive families, whose web, if they make a web, is a bellmouthed
tubular retreat. The Dysderidae have a peculiar sternum,
which overlaps the coxae of the legs, and the Oonopidae often have a
hard plate or scutum, covering the dorsal surface of the opisthosoma.
In the large cohort Argiopoidea the Argyronetidae include but one
species, the water spider, Argyroneta aquatica, familiar in Europe and
northern Asia. The Hahniidae are characterized by the peculiar
arrangement of their spinnerets which form a transverse line across the
hind-edge of the opisthosoma. The Anyphaenidae are a large family, so
are the Pholcidae; the others are all small and of local or very discontinuous
distribution.
The Dionycha are in general spiders which wander in search of their
food.
Five families are large and of cosmopolitan distribution. Of these the
Drassidae and Clubionidac represent the wandering mainly nocturnal
species, the Thomisidae and Sparassidac are flattened "crab-spiders"
which lurk hidden in crevices or, concealed by protective colouration,
lie in flovvers waiting for visiting insects, and the Salticidae are largeeyed
jumping-spiders, particularly numerous in the Tropics, which can
see and leap upon their victims at a distance of several inches. The other
families are only small groups.
The Trionycha include the peculiar
is much raised in front and the
in which the caput
articulate far above the
pedipalpi. Living forms are rare but exactly similar curiosities have been
found "fossilized" in Baltic amber.
The Mimetidae are well characterized by the spinal armature of
their legs, the Hersiliidae by their long tail-like spinnerets and the
Pholcidae by their elongated narrow bodies and very long legs.
Three families of this group are huntsmen, the Oxyopidae, Pisauridae
and Lycosidae, which pursue their prey and trust to speed to catch it.
The last two are numerous and very widely distributed.
The Agelenidae are a large family, spinning the ordinary cob-web, a
tubular resting-place the lower edge of which is continued into a wide
hammock, held by threads above and below.
18. THE ORDER ARANEAE 163
Finally there arc the three largest families: the Theridiidae, characterized
by a comb of setae on the tarsi of their fourth legs, small spiders
spinning an irregular maze of threads among leaves; the Linyphiidae,
including an enormous number of tiny spiders, often without pattern,
which spin a sheet of web and live upside-down, hanging from its lower
surface; and the Araneidae (-Epeiridae Argiopidae) whose web is
the familiar orb-web. All these spiders are spread throughout the world.
PALAEONTOLOGY
The Palaeozoic Araneae, of which at least 18 species have been
described, are of because no fewer than 12 of them belong
to the sub-order Liphistiomorphac. This sub-order, now limited to ten
species in :\1alaysia, China and Japan, was apparently the dominant
type of spider in those remote times, and was widely spread over the
northern hemisphere. These 12 species have been placed in two
wholly extinct families, the Arthrolycosidac, with tvvo genera and three
species, and the Arthromygalidae, with nine genera and nine species.
Protolycosa, the first of to be described, came in 1860 from
Kattowitz in Upper Silesia, two Arthrolycosa from Illinois, and Eoctenizia
from Coseley, \Vorcestershire. :\fast of the Arthromygalidae were
described from Nyran, Bohemia, in 1888 or 1904.
Three members of the Arachnomorphae have been found in Palaeozoic
strata, Eopholcus and Pyritaranea from the Carboniferous of
Bohemia and Archeometa from Coseley. No Palaeozoic 1v1ygalomorphae
have been found.
Records of Arachnida from J\fesozoic rocks are rare and onlv four or
five species have so far been discovered. All came from th'e oolitic
limestone ofPapenheim, Bavaria.
Tertiary formations, including amber, have yielded much more.
Theraphosomorphae are represented by Eoatypus from the Eocenc of
the Isle ofWight, and Eodiplurina from the Oligocene of?\orth America.
The sub-order Arachnomorphae is represented hy fossils from the
Miocene of Rott, Germany, and Aringen, Switzerland, and from the
Eocene of Aix, the Isle of Wight and Florisant, Colorado. The Carboniferous
type of Liphistiomorph is found not to have persisted in Europe.
The richest source of Tertiary spiders is Baltic amber, in which many
invertebrate remains have been found. These are treated in a separate
section in Part V.
Nearly 100 fossil species of Arachnomorphae have come from
sources other than Baltic amber: most of these have been found in the
Oligocene of Colorado, but France, Germany and Switzerland have
also provided examples.