260 H. S. Harrison, 



Outlines of ail figures drmvn tvith camera lucida.. 



Fig. 1. Transverse section through auditory capsule of adult Triton taeniatus, 

 in region of foramen perilymphaticum. The ductus perilymph aticus is 

 seen passing through the foramen to join the spatium meningeale {S. M). 

 x25. 



Fig. 2. Section slightly x^osterior to the last, showing the recessus fenestrae 

 vestibuli {R. V). The beginning of the diictus is seen passing into the 

 bony lateral canal, x 25. 



Fig. 3. More highly magnified view of the ventral region of the capsule in a 

 section just posterior to the last. The ductus is leaving the recessus; its 

 wall is considerably thickened, x 50. '' 



Fig. 4, 5. Transverse sections of Triton taeniatus at 31 mm. Fig. 4 illustrates 

 the pushing out of the membrane of the fenestra vestibuli by the re- 

 cessus {R. V). Fig. 5 is sliglitly further back, behind the posterior 

 margin of the fenestra, and shows the part of the recessus lying outside 

 the capsule. This figure also illustrates the convoluted course of the 

 ductus perilymphaticus {D. P). x 70. 



Fig. 6 — 11.^) A series of transverse sections through part of the auditory capsule 

 of young Siredon pisciformis. Figs. 6 and 7 show the recessus partis 

 neglectae (R. iV) , and the dxrctus {JD. P) , the latter running through the 

 foramen perilymphaticum to join the spatium meningeale (fig. 7, S M). 

 Figs. 8, 9, 10, 11 illustrate the relations between pars basilaris {p- b) 

 and recessus partis basilaris (R. ti). The sections drawn form the 

 series 1, 5, 7, 9, 10, 12; thickness 0,03 mm. x 50. 



Fig. 12. Transverse section of auditory capsule of the same specimen as last 

 sections, but on the opposite side. The very large empty space within 

 the capsule on the right is partly spatium sacculare, but is also due in 

 part to the effect of reagents, x 25. 



Fig. 13. Section through pars neglecta of adult Triton taeniatus, to show tliiniiess 

 of wall separating endolymphatic {p. n) and perilymphatic {R. IS) spaces 

 in this region (tympanal area), au is the brandi of the auditory nerve 

 wliich supplies the macula {mac) of the pars neglecta. x 300. 



Fig. 13'. Section through pars basilaris of Salamandra maculosa (adult), to show 

 tympanal area (in section-^?/) and the frame of specialized perilymphatic 

 tissue [sh). X 250. 



Fig. 14. Section through pars basilaris of Rana fusca (R. temporaria) larva (17 mm) 

 to show the tympanal area {iy). The wall of the pars basilaris is else- 

 where greatly thickened by "Spindelknorpel ", which forms a frame 

 ("Knorpelrahmen") for tlie membrane separating perilymph and endo- 

 lympli. (The membrane is seen partly in sui-face view.) x 300. 



Fig. 15—21. From transverse sections of Felobates fuscus larva (44 mm long). 

 Fig. 15 shows the ductus perilynii)haticus passing inwards and down- 



') Fig. 9 of iliis scries has brcu losi in transmission and is tlioi-oforc oiiiiilcil 

 from Plate XI. 



