196 



PRODUCTION OF DOUBLE EMBRYOS 



HINRICHS, M. A. G I. J. GENTHER, 1931 - "Ultra-violet radiation and the production of twins and double monsters. " Physiol. 



Zool. 4:461. 

 LYNN, W. G., 1938 - "Conjoined twins and triplets in trout. " Anat. Rec. 70:597. 

 MANGOLD, O., 1921 - "Situs inversus bei Triton. " Arch. f. Ent. mech. 48:505. 



NEWMANN, H. H. , 1940 - "The question of itiirro imaging in human one-egg twins." Human Biology. 12:21. 

 PASTEELS, J. , 1933 - "Recherches sur les facteurs initioux de la morphogenese chez les amphibienes anoures. I. Resultates de 



I'experience de Schultze et leur interpretation. " Arch. Biol. 49:629. 

 PENNERS, A. & W. SCHLEIP, 1928 - "Die Entwicklung des Schultzeschen Doppelbildungen aus dem Ei von Rana fusca. " Zeit. f. 



Wiss. 130:306. (Also ibid. 131:1.) 

 SCHWIND, J. L. , 1942 - "Spontaneous twinning in the Amphibia. " Am. Jour. Anat. 71:117. 

 SPEMANN, H., 1901 - "Entwicklungsphysiologische Studien am Triton-Ei. " Arch. f. Ent. mech. 12:224 (See also 15:448j 



16:551). 

 SPEMANN, H. , 1938 - "Embryonic development and induction." Yale Univ. Press. 

 SPEMANN, H. G H. FALKANBERG, 1919 - "Ueber asymmetrische Entwicklung und Situs inversus viscerum bei Zwillingen und 



Doppelbilungen. " Arch. f. Ent. mech. 45:371. 

 STRETT, J. C. Jr. , 1940 - "Experiments on the organization of the unsegmented egg of Triturus pyrrhoghaster. " Jour. Exp. Zool. 



85:383. 



TAIL 



HEAD 



CHIMERA - fusion of anterior ends of 

 Rana pipiens embryos. 



HEAD 



"If there is one broad pyinciple which emerges clearly from 

 experimental teratology , it is that all anonialies can no more be 

 treated as a single universe than can all rashes or all tumors. " 



Ingalls 



"The course from the primary cause of a malformation to 

 the observed defect frequently is not predictable. As Eerhardt 

 wrote, the same 'inciting event' ))iay produce several different 

 defects, and similar defects may result from dissimilar agents 

 or events. Some embryos exposed to a given 'insult' may die 

 and be aborted, yet others may go to term and survive despite 

 a gross malformation. " 



James D. Ebert, 1961 Jour. Chron. Dis. 13:91. 



