Complex sentence: Crampton made twelve separate expeditions over the course of his career to Moorea near Tahiti to study the land snail genus "Partula", while years more were spent measuring and cataloguing his specimens.
Split into simpler sentences: Crampton made twelve separate expeditions over the course of his career to Moorea near Tahiti to study the land snail genus "Partula". Years more were spent measuring and cataloguing his specimens.