386 Julia B. Platt 
which Goronowirscu concludes that the most extensively developed 
part of the neural crest in the bird has nothing to do with the 
development of nerves or ganglia, in consequence of which it is 
evident why the crest is largest in the region of the mid-brain. The 
massive production of mesodermic material appears where the widest 
part of the skull is to be formed. 
GORONOWITSCH finds that, in association with true mesodermic 
cells, part of the neural-crest cells give rise to a »nervenführenden« 
tissue through which the true nerve fibres ultimately make their 
way. A proliferation of cells from the ectoderm into the mesoderm 
at the margin of the gill clefts is also noted. 
This paper was followed by a short preliminary notice by JULIA 
Puatr (93) of the formation of the branchial cartilages in Neeturus 
from cells of ectodermic origin. 
In the final paper of GORONOWITSCH (93) we further find that 
the sheath of ScHWANN (page 212) arises from the nerve-supporting 
tissue which GORONOWITSCH describes as formed in part at least 
from cells of the neural crest, and it is suggested (page 216) that 
the mesenchyma-forming activity of the ectoderm in different regions 
of the head shows us that the origin of the cutis from the ectoderm 
is possible. Nothing is said regarding the origin of cartilage 
either in the branchial arches or elsewhere, but near the 
close of the paper (page 253) we read that the »periaxiale Stränge« 
may rather be associated with the development of the visceral arches 
than with the development of nerves, while on page 254, GORONO- 
wırscH adds, that he must leave for the present undecided whether 
the significance of the »periaxiale Stränge« in the development of 
the visceral arches consists merely in the fact that. they form a part 
of the musculature of the arches. The »periaxiale Stränge«. of 
GORONOWITSCH are composed of cells from two sources; dorsally of 
cells from the neural crest, and ventrally of cells proliferated from 
the mesoderm. The resultant tissue, however, is described as 
homogeneous. 
The fate of the neural crest in the Teleostei, GORONOWITSCH 
finds similar to that of the neural crest in the bird. 
The conclusions which I reach from the study of wandering 
ectodermic cells in Necturus differ widely from the conclusions 
reached by GORONOWITSCH in the study of the bony fish and bird. 
Owing to a passing differentiation, occasioned by unequal ab- 
sorption of yolk granules in the tissues of the head, the cells which 
