Complex sentence: However, in certain genera, it is found that species normally dextral will exceptionally produce sinistrally coiled shells, and vice versa and this abnormal growth probably is caused by disturbance of the relations of the embryo with its initial shell.
Split into simpler sentences: However, in certain genera, it is found that species normally dextral will exceptionally produce sinistrally coiled shells, and vice versa. This abnormal growth probably is caused by disturbance of the relations of the embryo with its initial shell.