Chelicera of spiders
This photo shows the chelicera of a spider being held open with a stick. Some chelicerae, such as those found in spiders, are hollow and contain (or are connected to) venom glands which are used to inject venom into prey or a (perceived) threat.
Source
Boundless vets and curates high-quality, openly licensed content from around the Internet. This particular resource used the following sources:
"Solifugae Chelicera lateral aspect 2012 01 24 0999s."
http://commons.wikimedia.org/wiki/File:Solifugae_Chelicera_lateral_aspect_2012_01_24_0999s.JPG
Wikimedia
CC BY.
