ectosarc

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

• noun The ectoplasm of certain protozoans, such as an amoeba.

from The Century Dictionary.

• noun The ectoplasm of a protozoan; the exterior substance of the body of an animal of low organization, as an amœba or other rhizopod or protozoan, in any way distinguished from an endosarc; the usually thicker, denser, tougher, or otherwise modified protoplasm which forms an envelop of the body, as differentiated from the interior substance or contents.

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

• noun (Biol.) The semisolid external layer of protoplasm in some unicellular organisms, as the amœba; ectoplasm; exoplasm.

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

• noun The ectoplasm of an amoeba and similar protozoa