Polybranchia

Proper noun

 * 1) Certain organisms bearing numerous branchia:
 * 2)  A group of  or the modern order, including those which have numerous branchiae on the back.
 * 1)  A group of  or the modern order, including those which have numerous branchiae on the back.
 * 1)  A group of  or the modern order, including those which have numerous branchiae on the back.