1. Alt A (1910) On the histology of the eye of Typhlotriton spelaeus, from Marble Cave, Mo. Trans Acad Sci St. Louis 19:83?96
2. Arnold W (1935) Das Auge von Hypogeophis. Beitrag zur Kenntnis der Gymnophionen XXVII. Morphol Jahrb 76:589?625
3. Brand DJ (1956) On the cranial morphology of Scolecomorphus uluguruensis (Barbour & Loweridge). Ann Univ Stellenbosch 32A:1?25
4. Brandon RA (1968) Structure of the eye of Haideotriton wallacei, a North American troglobitic salamander. J Morph 124:345?352
5. Burckhardt R (1891) Untersuchungen am Hirn und Geruchsorgan von Triton und Ichthyophis. Zeit Wiss Zool 52:369?370