Spider are apparently absent. In some species, the exocuticle of the legs and prosoma is modified by a tanning process, resulting in brown coloration. Bilins are found, for example, in "Micrommata virescens", resulting in its green color. Guanine is responsible for the white markings of the European garden spider "Araneus diadematus". It is in many species accumulated in specialized cells called guanocytes. In genera such as "Tetragnatha", "Leucauge", "Argyrodes" or "Theridiosoma", guanine creates their silvery appearance. While guanine is originally an end-product of protein metabolism, its excretion can be blocked in spiders, leading to an increase in its storage. Structural colors
Hyas coarctatus of the walking legs is often more or less furry. "H. coarctatus" is found at both hard, stony, sandy and soft bottoms from 1 to 500 meters depth, though most often above 50 meters. "H. araneus" inhabits shallower depths. "H. coarctatus" is widely distributed in the North-East Atlantic and adjacent seas. The northern border is around the north and west coas5w of Spitsbergen and Barents Sea, in the south it is found down to the north-east coast of France, and in the east to the Western Baltic Sea, the Belt Sea and the Öresund. Hyas coarctatus Hyas coarctatus is a