AUDITORS ORGAX. 207 



RELATION OF THE AUDITORY ORGAN TO THE AIR-BLADDER IX FISHES. 



A relation between the auditory organ and air-bladder is observable in four 

 families of Teleosteans (Silnroidei, Cyprinoidei, Characini, and Gymnoti). The 

 apparatus is formed on the same plan in all these Fishes. 1 



A chain of bones extends between the anterior end of the air-bladder and 

 the auditory organ, by means of which the relative fulness of the air-bladder 

 can be appreciated by the Fish. This chain arises by the metamorphosis of 

 certain parts of the four anterior vertebrae (upper arches and spines and 

 transverse processes), and four segments may be distinguished. In many cases 

 processes of the air-bladder are produced outwards to the side-walls of the body, 

 where the skin becomes very thin, forming a sort of tympanic membrane. 



(For further details, such as the relation of the whole apparatus to the 

 saccus endolymphaticus, the reader is referred to Wiedersheim's Lehrbuch der 

 vergl. Anatomic.) 



BIBLIOGRAPHY. 



HADDOX, A. C. On the. Stridulating Apparatus of Callomystax gagata. Journ. of 



Anat. and Physiol. Vol. XV. 

 HASSE, C. The numerous Papers of this Author, which refer to all the chief 



Vertebrate groups, are published partly in the Zeitsch. f. vriss. Zool. (Bd. XVII. 



und XVIII.), and partly in " Anaiomwchen Studien." Leipzig, 1870-1873. 

 HEXSEX, V. Physiologic des Gehors. In the Handbuch der Physiologic by L. 



Hermann. Abthl. Sinncsorgane 2. Leipzig, 1880. 

 His, W. Anatomic mensch. Embryonen. Leipzig, 1880-1885. 

 HOWES, G. B. On the Presence of a Tympanum in the Genus Raia. Journ. of Anat. 



and Physiol. Vol. XVII., 1883. 

 KTJHX. See the works of this Author on the auditory organ of Fishes, Amphibia, 



and Reptiles in the Arch. f. mikr. Anat. Bd. XIV., XVII., XX. 

 MOLDEXHAUER, "\V. Die EntwicJclung des mittleren und dusseren Ohres. Morph. 



Jahrb. Bd. ill., 1878. 

 PARKER, T. J. On the Connection of tlte Air-Bladder and the Auditory Organ in the 



Eed Cod (Lotella bacchus). Trans. N. Z. Institute, 1883. 

 RETZIUS, G. Das Gehdrorgan der Wirbelthiere. I. Das Gehdrorgan der Fische und 



Amphibien. Stockholm, 1881. //. Das Gehdrorgan der Reptilitn, der Vdgel, 



und der Sdugethiere. Stockholm, 1884. 



WEBER, E. H. De aure et auditu hominis et animalium. Lipsiae, 1820. 

 WIEDERSHEIM, R. Zur Anatomic und Physiologic des Phyllodactylus euroixeus, <tc. 



Morph. Jahrb. Bd. I., 1876. 



1 T. J. Parker has also described a connection between the auditory organ, air- 

 bladder, and skin in the Red Cod (Lotella bacchus). 



