The Collaborative International Dictionary of English v.0.48:

Halones \Ha*lo"nes\ (h[.a]*l[=o]"n[=e]z), n. pl. [NL., fr. Gr.
   "a`lwn, "a`lwnos, a halo.] (Biol.)
   Alternating transparent and opaque white rings which are seen
   outside the blastoderm, on the surface of the developing egg
   of the hen and other birds.
   [1913 Webster]