Complex sentence: Brisson believed his specimen had come from the Cape of Good Hope region of South Africa but when it was realized that the species did not occur in Africa it was thought that the specimen had been obtained on the Indonesian island of Java.
Split into simpler sentences: Brisson believed his specimen had come from the Cape of Good Hope region of South Africa. The species does not occur in Africa and it was thought that the specimen had been obtained on the Indonesian island of Java.