Crossword-Solution: BLASTOSPHERE 12 letters, 1 clue 🏆 scrabble score: 19

The fertilized ovum, the cell with which each animal begins its life, grows and multiplies by cell division, and develops into a hollow globe of cells called the BLASTOSPHERE.

Each of these early embryological stages is represented by living animals,--the undivided cell by the PROTOZOA, the blastosphere by some rare forms, and the gastrula in the essential structure of the COELENTERATES,--the subkingdom to which the fresh-water hydra and the corals belong.

The earliest one-celled protozoa were probably succeeded by many- celled animals of the type of the blastosphere, and these by gastrula-like organisms.

This layer of cells is called the germinal membrane (or blastoderm); the homogeneous cells which compose its simple structure are called blastodermic cells; and the whole hollow sphere, the walls of which are made of the preceding, is called the blastula or blastosphere.* (* The blastula of the lower animals must not be confused with the very different blastula of the mammal, which is properly called the gastrocystis or blastocystis.

The blastosphere may grow and expand by the blastodermic cells (at the surface of the sphere) dividing and increasing, and more fluid is secreted in the internal cavity.