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the sacculus), and that the papilla lagenae is found on a more distal 

 part of the wall of the lagena. From this it will be realized that 

 Alexander's diagram is quite inapplicable to the Urodela. It is 

 equally inaccurate if it is supposed to represent the condition in the 

 Anura. Here the terms proximal and distal have a very misleading 

 significance as applied to the relations of the lagena and pars basilaris 

 to the sacculus. The two lie side by side, internal to the posterior 

 portion of the sacculus, the lagena anterior and slightly ventral, pars 

 basilaris posterior and more dorsal. The openings of the two structures 

 into the sacculus are quite independent of each other, and the pars 

 basilaris cannot legitimately be said to be distal to the lagena — even 

 though it is posterior to it. 



The whole burden of probability of Dr. Alexander's view rests 

 upon the accuracy of the two diagrams I have reproduced. His 

 conception of the relations of the parts in the Amphibia is clearly 

 erroneous, and it is not too much to say, that, whatever may be the 

 true significance of the macula ductus reunientis, the suggestion that 

 it represents the papilla lagenae of the Amphibia, is devoid of all 

 probability. The older view cannot be regarded as being in any way 

 discredited, and the lagena of the lower Vertebrates must still be 

 looked upon as homologous with that of the higher. The homology 

 was first founded, in the main, on the examination of dissections of 

 the membranous labyrinth, and a study of the descriptions and figures 

 of Hasse, Retzius and Kuhn is alone almost sufficient to show that 

 Dr. Alexander has been hasty in rejecting the view hold by these 

 writers. The examination of series of sections through the labyrinth 

 of various Urodela, Anura and Reptilia leaves no doubt in my mind 

 as to the accuracy of their conception of the course of evolution of 

 the cochlea. As I have said above, the pars basilaris first appears 

 in certain Urodeles, and acquires a greater importance in the Anura. 

 The conditions in the Lacertilia (to which I have paid more attention 

 than to the other Reptilian groups) is easily deducible from that 

 found in the Amphibia. In Lacerta agilis for example, the cochlea 

 consists of a sac, situated chiefly below the sacculus, with which 

 it is connected by a short tube. It still retains marked indications 

 of its double origin. Although there is now only one opening into the 

 sacculus, a posterior pars basilaris can be distinguished from an 

 anterior lagena. The line of fusion is indicated by a ridge projecting 

 into the cochlear cavity, and the inner (medial) wall is distinctly 

 divided into two parts, the posterior part being unmistakably the 

 representative of the inner wall of the pars basilaris of the Amphibia. 



