ORIGIN OF AMPHIBIAN PIGMENT 271 



Twitty and Bodenstein (1939) found that pigment appears in the isolated chromatophores 

 when cultured in Standard (Holtfreter ' s) Solution later than in peritoneal fluid, they darken 

 less rapidly, and the melanophores become more widely dispersed. The active migration 

 of melanoblasts in vitro is confined to the period before the pigmentation is established, 

 in both species of Triturus studied, although migration does not preclude the possibility 

 of further melanization. They found, in general, that when the volume of the culture 

 nnedium was kept low that pigment development was the better, and small drops of peri- 

 toneal fluid were the best. Xanthophores appear more frequently in cultures of Ambly- 

 stoma than in cultures of Triturus crests. 



Szepsenwol (1945) found that the eyes of larvae (Amblystoma and Rana) effect the body 

 color either by a humoral substance (early in development) or reflexly (later in develop- 

 ment), when the nervous control of the melanophores dominates the humoral. These ob- 

 servations resulted from parabiotic union studies in which the eyes of one or both mem- 

 bers of the pair were excised, and subsequent pigment pattern studies were made. 



REFERENCES 



. ADLER, A. , 1939 - "Melanin pigment in the central nervous system of vertebrates. " Jour. Comp. Neur. 70. 

 ATWELL, W. J. , G E. HOLLEY, 1936 - "Extirpation of the pars intermedia of the hypophysis in the young amphibian with subse- 

 quent silvery condition and metamorphosis. " Jour. Exp. Zool. 73:23. 

 BALTZER, F. , 1941 - "Untersuchungen an chimaren von Urodelen und Hylo. I. Die Pigmentierung chimarischer Molch-und 



Axolotllarven mit Hyla-Ganglienleiste. " Rev. Suisse de Zool. 48:413. 

 BARDEN, R. B. , 1942 - "The origin and development of the chromatophores of the amphibian eye. " Jour. Exp. Zool. 90:479 



(See ibid. 92:171). 

 BEAMS, H. W. 8 R. L. KING, 1938 - "Pigmentation changes in tadpoles of Rana pipiens following centrifugation during the, 



early gastrula. " Jour. Morph. 63. 

 BYTINSKI-SALZ, H. , 1939 - "Chromatophorenstudien II. Struktur und Determination des adepidermalen Melanophorennetzes bei 



Bombina." Arch. f. Zellforsch. 22:123. 

 DALTON, H. C. , 1946 - "The role of nucleus and cytoplasm in development of pigment patterns in Triturus. " Jour. Exp. Zool. 



103:169. 

 DANNEEL, R. , 1957 - "Die ersten Melanoblasten der Neunaugenlarvae" Naturwissen. 2:46-47. 

 DAWES, Ben. 1941 - "The melanin content of the skin of Rana temporaria under normal conditions and after prolonged light and 



dark adaptations. " Jour. Exp. Biol. 18:26. 

 DeLANNEY, L. E. , 1941 - "The role of the ectoderm in pigment production, studied by transplantation and hybridization. " Jour. 



Exp. Zool. 87:323. 

 DETWILER, S. R. , 1937 - "Observations upon the migration of neural crest cells, and upon the development of the spinal ganglia 



and vertebral arches in Amblystoma. " Am. Jour. Anat. 61:63. 

 DETWILER, S. R. , G W. M. COPENHAVER, 1940 - "The growth and pigmentary responses of eyeless Amblystoma embryos 



reared in light and in darkness. " Anat. Rec. 76:241. 

 DORRIS, Frances, 1940 - "Behavior of pigment cells from cultures of neural crest when grafted back into the embryo. " Proc. 



Soc. Exp. Biol. G Med. 44:286. 

 DRAGER, G. A. , G R. F. BLOUNT, 1941 - "The time of the appearance of melanophore expanding hormone in the development 



of Amblystoma maculatum. " Anat. Rec. 81; suppl. 93. 

 DuSHANE, G. P., 1943 - "The embryology of vertebrate pigment cells. I. Amphibia." Quart. Rev. Biol. 18:109. 

 EASTLICK, H. L. , 1940 - "The localization of pigment-forming areas in the chick blastoderm at the primitive streak stage." 



Physiol. Zool. 13:202. 

 ELIAS, H. , 1943 - "Cause for blue, green, and red colour in Anura. " Anat. Rec. 87:12. 



ETKIN, W. , 1941 - "On the control of growth and activity of the pars intermedia of the pituitary by the hypothalamus in the tad- 

 pole." Jour. Exp. Zool. 86:113. 

 FOSTREDT, G., 1939 - "Preliminary in vitro studies of melanophore-principle activity of the pituitary gland. " Proc. Soc. Exp. 



GMed. 40:302. 

 HUMM, F. D. , 1942 - "The growth and migration of cultured melanophores from the neural crest when grafted into the embryo. " 



Jour. Exp. Zool. 90:101. 

 LEHMANN, F. E. , 1929 - "Die Entwicklung des Anlagenmusters im Ektoderm der Tritongastrula. " Arch. f. Ent. mech. 117. 

 LYNN, W. G. G Sr. A. de MARIE, 1946 - "The effect of thiouracil upon pigmentation in the tadpole." Science, 104:31. 

 MARSLAND, D. M. , 1945 - "The mechanism of pigment displacement in unicellular chromatophores. " Biol. Bull. 87:252. 

 NIU, M. C. , 1947 - "The axial organization of the neural crest, studied with particular reference to its pigmentary component. " 



Jour. Exp. Zool. 105:79. (See also 113:633, 1950) 

 NIU, M. C, 1954 - "Further studies on the origin of amphibian pigment cells. " Jour. Exp. Zool. 125:199-220. 



