What term describes the short appendages near a spider's anal opening that are used to spin silk?

The term that describes the short appendages near a spider's anal opening used to spin silk is "spinnerets." Spinnerets are specialized structures that are found in spiders, enabling them to produce silk threads for various purposes, such as building webs, creating draglines, or wrapping prey. These structures contain silk glands and can manipulate the silk as it is extruded, which is crucial for the versatility and efficacy of the silk that spiders create.

Pedipalps are sensory appendages that serve multiple functions, including manipulating prey and aiding in reproduction, but they do not play a role in silk production. Chelicerae are the mouthparts of spiders used for grasping and cutting food, and they do not relate to silk spinning either. Palps provide sensory assistance but are not responsible for spinning silk. Therefore, spinnerets specifically denote the structures responsible for silk production in spiders.