VITAL STAINING AND MORPHOGENET I C MOVEMENTS 



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Fig. 1. Camera-lucida drawing ol' a living Amblystoma punctatum embryo, made 1 day 



after operation. Nile-blue stained ^raft (shaded) as excised from the same 

 area in the donor as it now occupies In the recipient. The operation was 

 made at Harrison stage 30. The specimen is now about stage 31. For follow- 

 ing stages see Figures 2, 3, and 4. 



Fig. 2. Same living specimen as In Figure 1, shown second day after operation. The 

 shaded elongated club-shaped structure growing posteriorly from ectoderm of 

 graft (shaded) is the blue migrating mid-body lateral-line primordium. 

 Specimen is about stage 36. 



Fig. 3. Same specimen as in Figures 1 and 2, shown third day after operation. Note 

 beaded appearance of mid-body line primordium which has left in its trail 

 Dlue clumps (shaded) of cells that are forming lateral-line organs. The 

 short primordium of the dorsal body line (above limb region) from the graft 

 is also laying down segments for sense organs. Ectoderm of graft (shaded) 

 is still seen above second and third gill buds. Specimen is stage 37. 



Fig. 4. Same specimen as in Figures 1, 2, and 3, shown fourth day after operation. 

 Mid-Dody line primordium has oent dorsally (the normal course) above and 

 behind anal region and has moved caudally on t)ie tail. The tear-s)iaped 

 dorsal body line primordium (second portion of figure) has not quite 

 reached the position dorsal to the anal region where It normally termi- 

 nates. It did so later. The blue mid-body primordium, about 3 days later, 

 readied the tip of the tail and laid down a terminal blue organ at Harri- 

 son stage 44 (a larva with bidigitate fore limb and open mouth) . Note in 

 organs the dark ring about a light center and a peripheral light border. 

 For a later stage see Figure 13. Specimen is stage 3y. 



Development of the lateral-line organ ayatem aa Indicated by Nile Blue Sulphate- 

 stained graft of the anlage. 



( From Stone, 1955= Jour. Comp. Neur. 57=507) 



