EYE FIELD OPERATIONS 



29 1 



RANA PIPIENS 



LENS ANLAGE 



5 ..■•■ 



REGIONS OF OPTIC VESICLE 

 ANLAGE INDICATED BEFORE 

 CLOSURE OF FOREBRAIN 



STAGE 13-14 



OPTIC PROTUBERANCE 



A. 



STAGE 17 

 (34 HRS. LATER) 



DEFECT EXPERIMENTS 



EXCISIONS :* (See papers by Adelmann) 



1. Anura (stage #lU) or Urodela (stage #15) vr^^mrr fhn 



a. Study the accompanying schematized diagram of a neurula showing the 

 limits of the eye field. Eemove the ectoderm only from either area 

 "A" or area "B". 



-*% 



..^' 



^^.„ 



Camera-luclda drawing of a section through the prechordal 

 re'^ion of an Amblystoraa neurula (Harrison stage #lo) . ine 

 mesoderm has Just begun to separate from the lateral por- 

 tion of the roof of the archenteron. This gives an idea 

 as to the distribution of the (mesentoderm) substrate 

 referred to In the excision experiments. 



y 



Drawing from Adelmann 1950: Jour. Kxp. Zool. 57:223. 



* See section on "Wound Healing" for details of post-operative care. 



