193 
and therefore had no connection to the pharynx. A few fibres had 
grown into the lateral wall of the diencephalon immediately above the 
eye. In the normal position on the right side was a nasal anlage in 
an early stage of development. It had not yet developed fibres or 
made connection with the pharynx. 
Embryo 369, 2,5 mm long. No pigmentation or other evidence 
of the nasal plate is to be seen at this stage. A large area of ecto- 
derm in front of the right optic vesicle was transplanted on a denuded 
area above the optic vesicle of the same side. The nasal plate de- 
veloped’ in the transplanted epithelium simultaneously with that of the 
normal side. The embryo was killed the fourth day after the operation. 
The nasal anlage developed from the transplanted ectoderm is nearly 
as large as normal. It lies above the eye filling in the space between 
the ectoderm and the brain. It extends caudally from the nasal pit. 
There is of course no connection with the pharynx, the entire anlage 
lying above the eye. A large bundle of fibres goes from it into the 
lateral wall of the diencephalon above the eye. 
A very early stage in the development of a nasal anlage is seen 
in the normal position on the right side. That the regeneration had 
not gone farther in this case is to be attributed to the fact that the 
ectoderm did not cover the denuded area until the third day after the 
operation. 
In several embryos parts of the brain including the olfactory 
region were transplanted to see if the brain could induce the devel- 
opment of a nasal anlage from the ectoderm. In these experiments 
no external evidence of the formation of a nasal anlage over the trans- 
plantated brain tissue were noticed, but the embryos have not been 
sectioned yet. 
The following facts have then been experimentally obtained. 1) If 
the nasal anlage be removed at an early stage when it is represented 
by a pigmented thickening of the ectoderm, or if the ectoderm of that 
region be removed before a nasal plate has been formed, the nasal 
anlage may be regenerated to a practically normal condition having 
its usual connections to the brain and to the pharynx (Embryo 417). 
2) If the part of the brain that later forms the telencephalic lobe be 
removed at the 3 mm stage and the ectoderm left in position, the 
nasal anlage may develop and connect with the pharynx in a normal 
manner without sending fibres to the brain (Embryo 326). 3) The 
olfactory nerve fibres may develop in the nasal anlage when there is 
no connection with the brain (Embryo 325). 4) If the ectoderm of 
the nasal region be transplanted before the nasal plate has appeared 
Anat. Anz. XXIX. Aufsätze. 13 
