BIO21235. Cross-section of an ammonite. Ammonoids occupied the largest
Cross-section of an ammonite Ammonoids occupied the largest segments of the shell at the end of the coil; the smaller segments were filled with water, gas and air. At the embryonic stage the animal lived in its embryonic cell, protoconch, and as it grew it created its shell forming partitions behind itself. The successive stages remained intact, and embryonic, juveniles, adult and even senile stages have been found.