Protobranchia

Protobranchia

[‚prōd·ō′braŋ·kē·ə]
(invertebrate zoology)
A small and primitive order in the class Bivalvia; the hinge is taxodont in all but one family, there is a central ligament pit, and the anterior and posterior adductor muscles are nearly equal in size.
References in periodicals archive ?
Crystalline styles are found in all bivalve taxonomic groups except the subclass Protobranchia, and they also occur in some orders of herbivorous gastropods.