The screen consists of three frames, a photographic frame on the upper left, a text frame on the lower left, and an orientation frame on the right.
The photographic frames contain photomicrographic images of cross sections of a 33 hour chick embryo taken from a set of 300 serial cross sections. The photographs are numbered one to 15 out of a possible 15. A button below the photograph allows you to click and move to the following photograph.
The frame on the lower left of the screen is the text frame. The text consists of descriptive paragraphs that begin with a title that gives the section number out of the total number of 300 sections that comprise the embryo. A listing of the major visible features occurring at this particular level of sectioning follows the section number. Clicking on the title will bring the corresponding photograph into the photographic screen.
The orientation frame is located on the right hand side of the screen. This frame contains a thumbnail size diagram of the dorsal view of a whole 33 hour chick embryo. A vertical line indicates the level of sectioning of each cross sectional photograph. A button list, allows you to click and move to a previous section, the next section, the main menu, or the index.