22 The Paraphysis in the Common Fowl 
Ritter (11) also speaks of a parapineal organ which does not seem to 
me to have any resemblance to the one in question. It is certainly a 
good subject for future investigation, and with my present amount of 
material one ought soon to be able to arrive at some definite conclusion 
in regard to it. 
The presence of the supra-commissure in birds is denied by certain 
authors. Grénberg (8) states that it is not present in this class of ani- 
mals, but admits its presence in all the mammalia. Dejerine (3) claims 
that it exists in all vertebrates. It has been described under various 
neta 
site 
N he 
ans \ BN WG: 
ROSES BE AN 4 
aa nee’ QO ONS 
e OAKES 
Fic. 9. Embryo of 25 mm. Harvard Embryological Collection. Sagittal series 
516. Section 286. x 220 diams. 
names, but as far as I know, nothing has been said in regard to its de- 
velopment in birds, although Edinger (6) describes it in pigeons under 
the name of tractus habenulo-peduncularis. To Osborn (10) the simple 
name of supra-commissure is due. 
In Fig. 2 an embryo of 19 mm. the supra-commissure is met for the 
first time, and after this date it must of course persist throughout life. 
The various descriptions of its fibers seem to vary in the number of 
words employed, rather than in any real difference of opinion in regard 
to the anatomy of the commissure itself. As far as I know all writers 
agree that its fibers arise from the ganglion of the habenula, and termi- 
nate in the ganglion interpedunculare of the midbrain. 
