arcuate
A B C D E F G H I L M N O P Q R S T U V

isochela with the lateral alae clearly separated from the shaft which is usually curved outward, often bow-shaped. Together with anchorate isochelae they are called "tridentate" chelae as opposed to the palmate isochelae which have only a single independent (frontal) ala.

arcuate.jpg

from Atlas of Sponge Morphology