206 PROCEEDINGS OF THE AMERICAN ACADEMY. 



viduals were tested with the same colored lights, the rays toward the 

 blue end of the spectrum showed no such potency as compared with 

 those nearer the opposite end. It may be said that, while both the 

 skin and eyes are sensitive to the whole range of the visible spectrum, 

 color sensitiveness is present only in the latter. It is possible, how- 

 ever, that the supposed color sensitiveness is due to the effects of what 

 are intensity differences to the amphibian eye. 



(11) A decrease in the intensity of the light brings about a corre- 

 spondingly smaller number of positively phototropic responses and an 

 increase in the number of indifferent reactions. 



(12) The phototropic responses of eyeless toads are not due to 

 the stimulation of heat-receiving organs in the skin. Thermo- and 

 photo-reception are separate processes, and the former does not readily 

 give rise to tropic reactions. 



(13) Spinal amphibians gave no photic responses, but such reactions 

 were induced in animals in which the brain anterior to the meten- 

 cephalon had been excised. 



V. BIBLIOGRAPHY. 



Abelsdorff, G. 



:00. Zur Erforschung des Helligkeits- und Farbensinnes bei Menschen 

 und Thieren. Arch. £. Anat. u. Physiol., Physiol. Abth., Jahrg. 



1900, pp. 561-562. 

 Banta, A. M., and McAtee, W. L. 



:06. The Life History of the Cave Salamander, Spelerpes maculicaudus 

 (Cope). Proc. U. S. Nat. Museum, Vol. 30, pp. 67-S3, pis. 8-10. 



Beer, T. 



'98. Die Accommodation des Auges bei den Amphibien. Arch. f. ges. 



Physiol., Bd. 73, pp. 501-534. 

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1901, Nr. 11-13. 



BlCKEL, A. 



'97. Ueber den Einfluss der sensibelen N erven und der Labyrinthe auf 

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Cole, L. J. 



:07. An Experimental Study of the Image-forming Powers of Various 

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Cope, E. D. 



'89. The Batrachia of North America. Bull. U. S. Nat. Museum, No. 34, 

 525 pp., 81 pis. 



CONFIGLIACHI, P., E RESCONI, M. 



'19. Del Proteo Anguino di Laurenti Monographia. Pavia. (Known to 

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:06. The Frog Book. New York, xvii + 253 pp., 112 pis. 



