1. 80-82.? Missbildungen des Menschen. Leipzig. [With extensive atlas, in fol.]
2. 32.? Monstra animalium Duplicia.
3. 94.? Materials for the study of variation. Macmillan, London.
4. 93.? Les anomalies chez l'homme et les mammiferes. Paris.
5. 90.? Article ?Monsters? in Encyclopedia Britannica. 9th ed.