EFFECT OF CENTRIFUGATION ON DEVELOPMENT 



191 



The later stages of development, such as the blastula and gastrula, are to be centrifuged 

 within their jelly membranes and in the Standard Solution. 



Record the data in the following tables: 



TABLE I: CENTRIFUGATION. 



X GRAVITY 



TABLE II: CENTRIFUGATION. 



X GRAVITY 



Some of the types of abnormalities produced by centrifugation are: depigmentation, per- 

 manent blastulae; inhibition of gastrulation, anaxial and hypaxial conditions, doubling of 

 embryos, spina bifida, head defects, and accessory appendages. These should be photo- 

 graphed or sketched below, always with a record of the stage and conditions of centrifuga- 

 tion. 



REFERENCES 



BANTA, A. M. G R. A.- GORTNER, 1915 - "Accessory appendages and other abnormalities produced in amphibian larvae through 



the action of centrifugal force. " Jour. Exp. Zool. 18:437. 

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



early gastrula." Jour. Morph. 63:477. 

 BRACHET, J. , 1947 - "Localisation de I'acide ribonucleique et des proteines dans I'avaire de Grenouille normal et centrifuge. " 



Experientia III/8. 

 COSTELLO, D. P., 1940 - "The fertilizability of nucleated and non-nucleated fragments of centrifuged eggs. " Jour. Morph. 



66:99. 



