\Mar"si*po*bran"chi*a\, n. pl. [NL., fr. Gr. ? a
pouch + ? a gill.] (Zo["o]l.)
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}.