I think this is a double T-Rex embryo because we can see the umbilical cords in both heads. On the right top beneath the nose area are two umbilical cords leaving the mouth. It seems like an arm is formed by the hole, and another head is behind it.
This is the back with one head on the top left. When I look into those holes, it looks like tissue and maybe some teeth are forming. Very interesting!
It seems to me that they have both developed arms. Look at the top right corner and you will see the eye and a nostril. Beneath that looks like teeth. I can see a small umbilical cord leaving the mouth area. By the side of the face is an elbow of the one on top. It is 3.75″ x 2.5″ x .65″