blastosphere

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

From The Elements of Geology by William Harmon Norton

Such a sphere is called a blastosphere, and may be regarded as a spherical mass of protoplasm, of which the central portion is so much vacuolated that it seems to consist entirely of fluid.

From Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 3 "Electrostatics" to "Engis" by Various

The conditions for the origin of the blastosphere come into existence only by the process of segmentation, and it is only by its capacity to divide that the egg contains the conditions for blastosphere formation.

From The Biological Problem of To-day Preformation Or Epigenesis? The Basis of a Theory of Organic Development by Oscar Hertwig

The blastosphere of the frog is like what the blastosphere of amphioxus would be, if the future hypoblast cells were enormously larger through their protoplasm being diluted with yolk.

From Text Book of Biology, Part 1: Vertebrata by H. G. (Herbert George) Wells

The cells of the lower half of the blastosphere are slightly larger than those of the upper half.

From The Whence and the Whither of Man A Brief History of His Origin and Development through Conformity to Environment; Being the Morse Lectures of 1895 by John Mason Tyler