B 



Fig. 129, A-J. — Heteroplastic grafts in pharyngeal region. A, E, F, Dugesia iigrina to 

 D. dorotocephala; B, G-J, D. Iigrina novangliae to D. dorotocephala; C, D, D. doroiocephala to 

 D. Iigrina novangliae. A, DDAA* union complete, 42 days; tubular outgrowth developed 

 ventrally, covered with ventral epithelium and with two supernumerary eyespots, one shown 

 at S. B, DDAP, union complete, 35 days; original eyespots disappeared and four pigmented 

 areas developed, tail-like outgrowth from right side of host anterior to graft; host, decapitated 

 at X, failed to regenerate. C, DDAP, union complete, 42 days, ventral view; tubular out- 

 growth with terminal eyespots from large graft; host, decapitated about 3 mm. from graft, 

 regenerated only small amount of new tissue at A. D, DDAP, large graft union, complete, 28 

 days; pharynx with reversed polarity induced anterior to graft; extent of graft dominance 

 anteriorly indicated by anterior reorganization of digestive tract; after section at A^Y host 

 failed to regenerate. E, DDAA, large graft, 31 days, union complete, but graft given a free 

 posterior surface by section 7 days after implantation ; with development of head from posterior 

 side of graft its polarity is completely reversed. F, the animal of E at 74 days; the graft has 

 retained specific characters and has reversed polarity in a part of the host, as indicated by 

 ciliary movement, orientation of pharynx, and regeneration of a tail after fission from a level 

 originally anterior to the graft. G, DDAP, 14 days; anterior surface of graft failed to unite 

 with host; head (0) has developed from host portion of tubular outgrowth and small pharynx 

 has been induced anterior to the graft. //, the posterior part of the animal shown in G after 

 section at XX, with posterior end regenerated from the originally anterior surface of section. 

 /, DDAA, 21 days; left side of graft failed to unite with host and host lateral to graft tore 

 apart; modification of graft polarity indicated by position of auricles in relation to the eye- 

 spots. /, following decapitation of / at XX, tail and second pharynx were induced in host 

 anterior to the graft (from J. A. Miller, 1938). 



* In this figure and in Fig. 131 orientation of the graft in relation to the host is given in the notation adopted 

 for amphibian limb grafts by Harrison (p. 390); "DDAA" means that dorsal and anterior sides of graft are toward 

 dorsal and anterior of ho.st, that is, the graft is normally oriented; "DDAP," graft in normal dorsiventral, reversed 

 anteroposterior orientation. 



