2S0 
DR. U. PRITCHARD ON THE COCHLEA 
unsoftened preparations filed down, I was able to get a very clear demonstration of the 
relative position of the parts. 
But all these methods, and in fact the whole research, would have failed had it not 
been for the very prompt and careful manner in which the skulls were prepared and 
preserved before they were sent over to England, and for which kindness I desire here 
to offer to my Australian friends my sincere and heartfelt thanks. 
Description of Plates. 
Fig. 1. Longitudinal section through Duckbill’s cochlea. X barely 20 diameters. 
1. Opening into vestibule. 
2. Apex, or anterior extremity of cochlea. 
3. Helicotrema, the communication between the scake tympani and 
vestibuli. 
4. Cavity of lagena ; (-*—tube connecting it with ductus c-ochlese. 
5. Upper surface of lamina ossea. 
6. Upper surface of organ of Corti, (a) membrane of Beissner covering 
organ of Corti, &c., (a') ditto turned back. 
7. Ligamentum cochleae cut through. 
Fig. 2. Transverse section through Duckbill’s cochlea (middle), from No. 27 of series. 
X 75 diameters. 
1. Scala tympani. 
2. Scala vestibuli. 
3. Scala media or ductus cochleae. 
4. Lamina ossea, (a) nerve with ganglion. 
5. Ligamentum cochleae, (c) blood-vessels, ( b ) stria. 
6. Membrane of Beissner. 
7. Organ of Corti, ( cl ) membrana tectoria, ( e ) membrana basilaris, ( f ) 
marginal sulcus. 
Fig. 3. Transverse section through Duckbill’s cochlea (vestibular end), from No. 38 of 
series. X 22 diameters. 
1. Scala tympani. 
2. Scala vestibuli. 
3. Scala media or ductus cochleae. 
4. Lamina ossea. 
5. Ligamentum cochleae. 
6. Membrane of Beissner. 
7. Membrana basilaris. 
