This very common spider is often seen on window frames, but can also be found on walls, bark, rock faces etc. It spins an orb web with a "missing" sector. At this point, a signal line is run from the centre of the web to the spider, cocooned on the edge of the window frame or other habitat. The photo is of a female Zygiella x-notata attempting to spin a web on a large single paned French window.
Head and chelicerae of male Zygiella x-notata
Head and chelicerae of female Zygiella x-notata
Left Pedipalp (male sexual organ) of Zygiella x-notata
Chelicerae of a male Zygiella x-notata
Epigyne (female sexual organ) of Zygiella x-notata
Right pedipalp of Zygiella x-notata, ventral view. This view is not used for identification, but provides more information on the structure of the palp.
Spinnerets of a female Zygiella x-notata
Pedipalp of a female Zygiella x-notata
Tarsal claw of Zygiella x-notata, clogged with silk