631 



die Pars basilaris cochleae zwischen Macula sacculi und Papilla lagenae 

 entstehen, nicht aber als Anhanggebilde der Lagena. Dann läge ein- 

 heitlich der 'Lagena' genannte Abschnitt mit seiner Nervenendstelle 

 distal von der Pars und Papilla basilaris. Dies ist aber nicht der Fall, 

 und daher schlage ich vor, zwei 'Lagen ae' voneinander zu unterscheiden." 



The two "Lagenae" he proposes to distinguish are the "Lagena 

 sacculi" of Fishes and Amphibians, and the "Lagena cochleae" of 

 Reptiles, Birds and Mammals. Finally he says : "Danach erscheint die 

 Maculaanlage des Ductus reuniens des Meerschweinchens der Papilla 

 lagenae der Fische und Amphibien, der Ductus reuniens selbst der 

 Lagena sacculi dieser Tiere homolog"; but at the end of the paper 

 there is a foot-note to this suggestion, and in this he admits the 

 possibility that his "Macula ductus reunientis" is the long-lost macula 

 neglecta of Mammals. He thinks, however, there is little probability 

 of this being the case. 



We may first see how Dr. Alexander's topographical argument 

 completely breaks down when examined. According to him, in the 

 Amphibia the pars basiliaris lies distal to the lagena, whilst in the 

 Sauropsida the relations are reversed. If this were so, the two dia- 

 grams I have reproduced from his paper would represent the con- 

 ditions with sufficient accuracy, and we should have occasion to recon- 

 sider our faith in the homology of the lagena throughout the Verte- 

 brata. As regards his diagram of the Sauropsidan pars inferior, it 

 may be accepted without comment, but that of the Amphibian cochlea 

 cannot be justified by any of the figures of Hasse or Retzius, and 

 corresponds to nothing that I have myself observed. As far as I know, 

 no Amphibian labyrinth has been described, of which it would be 

 possible to say that the pars basilaris is distal to the lagena. The 

 term distal cannot be used in any accurate description of the inter- 

 relationship of the two structures, and their connections cannot be 

 represented, even diagram atically, as a "geradegestreckt als Schlauch 

 verlaufenden Pars inferior". In those Urodeles that possess a pars 

 basilaris, this is found at the upper end of the lagena, arising near 

 the upper border of the opening connecting the cavities of the lagena 

 and sacculus 1 ). The macula of the pars basilaris is therefore nearer 

 to the sacculus than is that of the lagena, and if we wished to use 

 the terms distal and proximal in this connection we should have to 

 say that the pars basilaris is an evagination of the proximal end 

 of the lagena (i. e. of that end which is nearest to the opening into 



1) See Figs. 10, 11, and 13' in my previously mentioned paper (6). 



