earless seal

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Any of various seals of the family Phocidae, which includes the harbor seal and elephant seals, characterized by short fore flippers, hind flippers specialized for swimming, a coat of short sleek hair, and the absence of external ears.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Any of the seals in the taxonomic family Phocidae characterized by lacking external ear flaps; true seals.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun any of several seals lacking external ear flaps and having a stiff hairlike coat with hind limbs reduced to swimming flippers