Invertebrate Biology Glossary

noun The first pair of appendages in most arachnids, typically modified for feeding and sometimes for defense.

• The chelicerae of spiders are the structures that contain their fangs.
• Did you know that a spider's chelicerae are used to inject venom into their prey?
• Watch out for those chelicerae, they can pack a mean bite!
• Her sharp words were like the chelicerae of a spider, injecting venom into the conversation.

noun a small, tentacle-like structure found in certain cnidarians such as hydras

• The actinula is a larval form of certain hydroids that is capable of swimming.
• Have you ever seen an actinula swimming around in the water?
• I heard actinulas are like the little swimmers of the ocean.
• The actinula represents a stage of growth and development in the life cycle of hydroids.