350 



THE EYE IN EVOLUTION 



and crude. The violet rods of the mvid-puppy, Necturus, for example, are enor- 

 mous, two and a half times the thickness of the corresponding structures in the 

 frog and the largest known in the vertebrate phyhim. The optic nerve fibres are 

 relatively few, one ganglion cell subserving more visual elements than in the frog 

 (Burkhardt, 1931). Thus there are, according to Palmer's (1912) heroic counting, 

 only 962 nerve fibres subserving the 53,000 rods, 42,000 single cones and 15,000 

 double cones in the retina. 



Angelucci. Arch. Anat. Physiol., 5-6, 363 



(1878). 

 Aoyama. Folia Anat. jap., Tokyo, 6, 829 



(1928). 

 Arey. J. co7np. Neurol., 26, 121, 429 



(1916). 

 Babixchin. Wiirzburg. naturwiss. Z., 4, 71 



(1863) ; 5, 141 (1864). 

 Beer. Pflugers Arch. ges. Physiol., 73, 



501 (1898). 

 Boll. Arch. Anat. Physiol., 4 (1877). 

 Boulenger. The Tailless Batrachians of 



Europe, London (1896). 

 Brown-Sequard. J. Physiol. Path, gen., 



2, 281 (1859). 

 Burkhardt. Z. vergl. Physiol., 15, 637 



(1931). 

 Cajal. La cellule, 9, 1 (1893). 

 Carasso. C. R. Acad. Sci. (Paris), 238, 617 



(1954). 

 Caso. Lettura Oftal., 8, 339 (1931). 

 Chievitz. Arch. Anat. Physiol., Anat. 



Abt., 139, 332 (1889) ; 311 (1891). 

 Cuignet. Ann. Oculist. (Paris), 55, 128 



(1866). 

 Denton and Pirenne. J. Physiol., 116, 



33P (1952). 

 Detwiler. Vertebrate Photoreceptors, N. Y. 



(1943). 

 Dobrowolsky. Arch. Anat. Physiol., 320 



(1871). 

 Dogiel. Anat. Anz.. 3, 342 (1888). 

 Engelhardt. Jena. Z. Naturwiss., 60, 241 



(1924). 

 Englemann. Pfliigers Arch. ges. Physiol., 



35, 498 (1885). 

 Froriep. Hertwig's Hb. d. vergl. exper. 



Entwicklungslehre d. WirbeUiere, Jena, 



2 (2) (1906). 

 Garten. Graefe-Saemisch Hb. d. ges. 



Augenheilk., II, 3, Kap. 12, Anhang 



(1907). 

 Gaupp. Eckers and Wiederscheimer's Atiat. 



des Frosches,Z (1904). 

 Greeff. Oraefe-Saemisch Hb. d. ges. 



Augenheilk., II, 1 (2), Kap. 5, 74 



(1899). 

 Gross. Zool. Jb., Abt. Anat., 17, 763 



(1903). 

 GrynfeUt. Bib. Anat. (Paris), 15, 177 



(1906). 

 C. R. Assoc. Anat., Lille (1907). 

 Guth. ' 'Ggers Arch. ges. Physiol., 85, 



lu: h). 



v. Hess. rch. vergl. Ophthal., 1, 153 



(1910 . 



Vergl. Physiol, d. Gesichlssinnes, Jena 



(1912). 

 Hesse. Zool. Jb., Abt. Syst., Suppl. 7, 471 



(1904). 

 Hirschberg. Arch. Anat. Physiol., 81 



(1882). 

 Hoffmann. Niederl. Arch. Zool., 3, 45 



(1876-77). 

 Hulke. Roy. Land, ophthal. Hosp. Rep., 



4, 243 (1864). 

 Hyrtl. ;S'. B. Akad. Wiss. Wien., 43 (1861). 

 Inagaki. Keijo J. Med., 1, 49 (1930). 

 Johnson. Philos. Trans. B, 215, 315 



(1927). 

 Jokl. Anat. Anz., 51, 209 (1918). 



Anat. Hefte, 59, 211 (1920). 

 Kessler. Entwicklung des Auges der 



Wirbelthiere, Leipzig (1877). 

 Khau-van-Kien. C. R. Assoc. Anat., 82, 



907 (1954). 

 Kolmer. Anat. Anz., 25, 102 (1904). 

 Krause, W. v. Graefes Arch. Ophthal., 21 



(1), 296 (1875). 

 Internat. Mschr. Anat., 9, 150 (1892). 

 Kiihne. Untersuch. a. d. physiol. Inst. d. 



Univ. Heidel., 1, 15, 455 (1878). 

 Kurose. Acta Soc. ophthal. jap., 60, 621 



(1956). 

 Kutsukaka. Acta Soc. ophthal. jap., 56, 



988 (1952). 

 Landolt. Arch. mikr. Anat., 7. 81 (1871). 

 Lauber. Anat. Hefte, 20, 1 (1902). 

 Leuckart. Graefe-Saemisch Hb. d. ges. 



Augenheilk., 1, 2, 145 (1876). 

 Maggiore. Ricerche morfol. sulV apparato 



palpebrcde degli Anfibi, Roma (1912). 

 Magnus. Z. Biol., 20, 567 (1899). 

 Majima. v. Graefes Arch. Ophthal., 115, 



286 (1925). 

 Mann. Trans, ophthal. Soc. U.K., 49, 353 



(1929). 

 Proc. Zool. Soc. Lond., 21, 355 (1931). 

 Mayer. ^na<. ^nz., 21, 442 (1902). 

 Millot. Le pigment purique chez les 



vertebres inferieurs, Paris (1923). 

 Miiller, H. Z. wiss. Zool., 8, 1 (1857). 



Wurzburg. naturwiss. Z., 2, 139 (1861). 

 Miiller, J. Vergl. Physiol, d. Gesichts- 



sinnes, Leipzig (1826). 

 Noble. The Biology of the Amphibia, N. Y. 



(1931). 

 Okajima. Z. wiss. Zool., 94, 171 (1909). 

 Palmer. J. comp. Neurol., 22, 405 (1912). 

 Petit. Mem. Acad. Sci., A, Paris, 142 



(1737). 



