242 



PARAB lOS IS AND TELOBIOS IS 



Parabiosis means lateral fusion. This may be side-to-side; back-to-back; belly-to- 

 belly; or a Combination of these. The slde-to-slde fusion is generally the best because 

 the larvae are permitted to move about and to feed in quite a normal manner. The lateral 

 fusion of three embryos has been achieved. 



TELOBIOS IS 



The technique of terminal fusion is identical with that above except that the Permo- 

 plast depression is long and narrow, and the injured areas are terminal rather than lateral. 

 Simply cut off the tip end of the heads, tails, or combinations, using sharp and sterile 

 scalpel or scissors. Bring the cut surfaces together and hold them approximated until 

 healed. The relations may be head to head; tall to tail; or head to tail. Also, one of 

 the embryos can be Inverted. 



OBSERVATIONS MP TABULATION OF DATA : 



a. Determine the growth rate of paired embryos as compared with the controls. 



b. Is there any evidence of dominance of one member of the pair over the other? 



c. How large a discrepancy in stages can be used for successful parabiosis? Dis- 

 crepancy in species? (See section on "Transplantations".) 



The data should be recorded in the form of photographs or drawings, and preserved 

 specimens which survive to the later stages. 



FUSED AT STAGP. 16 



DIED AND PHOTOGRAPHED 

 AT 73 DAYS OF AGE 



Raiin plpiens tadpoles in parabiosis, 

 fused at stage 16 photographed at 

 stage 24 (Railey) , 



PARABIOSIS IN METAMORPHOSED FROGS 

 (RANA PIPIENS) 



Tullpan & Schrelber, 191^2 



