Complex sentence: With French embryologist Étienne Serres (1786--1868), the "Meckel-Serres Law" is named, which was a theory of parallelism that attempted to link comparative embryology with a unifying pattern in the organic world.
Split into simpler sentences: With French embryologist Étienne Serres (1786--1868), the "Meckel-Serres Law" is named. This was a theory of parallelism which attempted to link comparative embryology with a unifying pattern in the organic world.