Grunion Development: Day 8

The eyes are fully pigment, and the body as well. The body has grown to such a length that it wraps around the inside of the egg a little over 2 times. The oil droplets have been completely depleted, and there is a little yolk left. What you can't see is that the embryo is very active, with eye and body twitches being quite common.

Grunion Development: Day 6

The embryo has grown, with the tail wrapping all the way around the egg and back around the head. The eyes have a lot of pigment and the body is starting to get a little pigment. The oil droplets are almost all used up and the yolk has a lot of blood vessels connecting it to the embryo.

Grunion Development: Day 4

The embryos are noticeably larger, and structures are becoming readily apparent. You can see the nerve cord running down the center of the embryo. gill arches forming behind the eye, and the eye itself has an indented pupil.

What you can't tell from the picture is that the heart is also nociable and pumping, and there are musculature visible along the length of the tail.

Grunion Development: Day 3

Now you can clearly see many features of the developing embryo. It has also grown large enough to wrap around the back of the egg, with the tail just peeking out on the left hand side. The oil droplets are being used up and condensed into one large drop right in the center.

Grunion Development: Day 2

Now it's approximately 37 hours after fertilization. You can still see the oil droplets off to the left, but the embryo has under gone some big changes. Instead of being a cap of cells it now has a definite form, with the head and developing eyes in the center, and the rest of the body trailing off to the top right.