217 
of development, the name ,,anterior epiphysis‘ is suggested. The 
hypothesis of SELENKA that it is a degenerate sense organ, is certainly 
questionable much more that its ancestral function was audition. 
The variation in the point of origin of the paraphysis, and its 
formation at a much later period than the epiphysis, would seem to 
indicate a less important ancestral function. The phylogenetic import- 
ance of the epiphysis is certainly indicated by the fact that it is 
formed at a fixed point throughout the vertebrate phylum. While it 
must be admitted that we are without evidence sufficient to warrant 
us in making any very definite statement, since if the organ is rudi- 
mentary its development may be retarded, yet its ontogeny indicates 
that it arose at a time when a neural canal was first formed. If we 
admit the hypothesis, which I believe I have proved in Amblystoma 
and Rana, that the lateral eyes are present as a pair of depressions 
in the cephalic neural plate, we might anticipate that at the phylo- 
genetic period when they became implicated by the closing of the 
neural folds a median eye would arise and become most highly func- 
tional during the period which the lateral eyes were non, or least, 
functional. This might explain the origin of the epiphysis as an un- 
paired organ. The circumstances which gave rise to another sense 
organ, if such the paraphysis be considered, are extremly difficult to 
explain. 
I may say that the results of my researches on the development 
of the lateral eyes are forthcoming in the Journal of Morphology, 
where I hope to establish, beyond question, that they are present as 
distinctly differentiated areas at the time the medullary groove first 
appears. 
Nachdruck verboten. 
Die Membrana peri-oesophagealis. 
Notiz von Dr. Stemunp Mayer, o. 6. Professor der Histologie und Vor- 
stand des histologischen Instituts an der deutschen Universität zu Prag. 
Im Jahre 1890 hat L. Ranvier in den Comptes rend. der Pariser 
Academie (Bd. CXI, pag. 863) eine kurze Mitteilung unter dem Titel: 
„De la membrane du sac lymphatique oesophagien de la Grenouille“ 
veröffentlicht, und darauf hingewiesen, daß diese Membran wegen 
ihrer sehr großen Dünnheit, und ihres Gehaltes an Blutgefäßen 
