amphiaster

from The Century Dictionary.

• noun [lowercase] A sponge-spicule consisting of a straight axis with a whorl of rays near each end.
• noun A genus of starfishes, of the family Goniasteridæ.
• noun [lowercase] In embryology, a formation in a maturing ovum of a fusiform figure radiated at either end, thus resembling two stars joined together, whence the name. See extract.

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

• noun (Biol.) The achromatic figure, formed in mitotic cell-division, consisting of two asters connected by a spindle-shaped bundle of rodlike fibers diverging from each aster, and called the spindle.

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

• noun biology The achromatic figure, formed in mitotic cell division, consisting of two asters connected by a spindle-shaped bundle of rod-like fibres diverging from each aster.