The Collaborative International Dictionary of English v.0.48:

Morula \Mor"u*la\, n.; pl. Morulae. [NL., dim. of L. morum a
   mulberry.] (Biol.)
   The sphere or globular mass of cells (blastomeres), formed by
   the clevage of the ovum or egg in the first stages of its
   development; -- called also mulberry mass, segmentation
   sphere, and blastosphere. See Segmentation.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Blastosphere \Blas"to*sphere\, n. [Gr. blasto`s sprout + E.
   sphere.] (Biol.)
   The hollow globe or sphere formed by the arrangement of the
   blastomeres on the periphery of an impregnated ovum.

   Note: [See Illust. of Invagination.]
         [1913 Webster]

WordNet (r) 3.0 (2006):

blastosphere
    n 1: early stage of an embryo produced by cleavage of an ovum; a
         liquid-filled sphere whose wall is composed of a single
         layer of cells; during this stage (about eight days after
         fertilization) implantation in the wall of the uterus
         occurs [syn: blastula, blastosphere]