marsipobranchia

from the GNU version of the Collaborative International Dictionary of English.

• noun plural (Zoöl.) A class of Vertebrata, lower than fishes, characterized by their purselike gill cavities, cartilaginous skeletons, absence of limbs, and a suckerlike mouth destitute of jaws. It includes the lampreys and hagfishes. See cyclostoma, and lamprey. Called also Marsipobranchiata, and Marsipobranchii.