FATE OF NEURAL CREST IN HEAD OF URODELES 5 
(Platt, ’96, ’97) this is questioned, and as a consequence she 
discards the term mesentoderm. In these later papers she 
derives ganglia, nerves, mesenchyme, and branchial cartilages 
and the dentine of the teeth from the mesectoderm, but neither 
muscles nor embryonic nerve supporting tissue (sheath of 
Schwann). In Miss Platt’s second paper (’94) she follows the 
ectoderm cells into the gill bars, but not to their complete differ- - 
entiation into cartilage. The later history of these cells and 
their differentiation into cartilages was given in the paper pub- 
lished in 1897. ‘ 
Later papers by Kupffer (95), by Lundborg (’99), by Dohrn 
(02), and by Brauer (’04) support in the main Miss Platt’s 
contention. However, Rabl (’94), Corning (99), Minot (01), 
and Buchs (’02) do not agree with her interpretation. The 
criticisms of Miss Platt’s theory will be given first. 
Rabl (94) at the Strassburg meeting of the Anatomische 
Gesellschaft criticised Goronowitsch’s description of the mode of 
derivation of the mesenchyme from ectoderm in birds and teleosts 
as an assumption, because Goronowitsch admitted that after 
ectoderm cells fuse with mesoderm he could no longer follow 
them, and consequently he had no right to assume that they 
became a permanent part of the mesenchyme. ‘This objection 
seems to be valid so far as birds and bony fishes are concerned. 
His objection to Miss Platt’s mode of derivation of cartilage 
is based not on a study of Necturus, which he admits he has not 
examined, but on a study of Triton, salamander, and axolotl. 
He thinks that the appearance, which Miss Platt finds in her 
preparations, of.cells being proliferated from the ectoderm, can 
be explained best as due to faulty fixation. Rabl makes a vigor- 
ous defense of the idea of the integrity of the germ layers. Most 
of his criticism is devoted to Klaatch’s (94) conception of the 
origin of the skeleton of the fins of the fishes. Harrison (’95) 
has since shown that Klaatch was wrong in his interpretation. 
Corning (’99) derives, in the Anura, from the neural crest, 
only ganglia and nerves, the ventral portions of which extend 
well down into the corresponding branchial arches. The neural 
crest is closely fused with the lateral ectoderm, deriving some of. 
