EAR-SWIMBLADDER RELATION IN CLUPEOIDS 233 



cilia are embedded. The chambers as they appear in fixed 

 material are produced by shrinkage of the membrane substance 

 away from the cilia. 



De Beaufort has briefly mentioned the macula acustica in 

 the Clupeidae. He says ('09, p. 619) : "Mit dem utriculus 

 existiert daher keine Verbindung, wohl liegt aber seine ventrale 

 Flache mit der Macula acustica oberhalb der erwahnten Off- 

 nung der Bulla." Tysowski gives a figure ('09, fig. 1) in which 

 the macula is shown lying over the fenestra of the bulla. His 

 figure seems to show the division of the organ into three parts, 

 but he makes no mention of it in his text. 



THE FUNCTION OF THE EAR-SWIMBLADDER RELATION IN 



CLUPEOIDS 



The swimbladder has a complexity of function correlated 

 with the diversity of its anatomical structure. Bridge and 

 Haddon ('93) thus summarize the functions which have been 

 attributed to the organ in different species of fishes: 1) phona- 

 tion, 2) respiration, 3) accessory to audition, 4) purely hydro- 

 static. The swimbladder of many species probably has more 

 than one of these functions, but different functions in varying 

 degrees. Hence, its physiology is a complicated problem which 

 requires for complete solution a separate investigation in each 

 of the structural types of the organ. Results of experimental 

 work on fishes with a certain type of the organ can hardly be 

 assumed to apply in every case without modification to fishes 

 having a different type. Moreau (76) and Baglioni ('08) have 

 laid the foundation of our knowledge of the general physiology, 

 but on the function of the specialized types of the swimbladder 

 very little recorded experimental work can be found. An ex- 

 ception to this statement is the work of Tower ('08) on the 

 sound-producing function of the organ in certain groups of 

 fishes. 



The ear in fishes is also an organ of complicated physiology. 

 Audition and equilibration are functions usually assigned to 

 this organ, but experimental evidence on the differentiation of 

 functions in the different parts of the membranous labyrinth is 

 incomplete (Lee, '98; Parker, '08). 



THE JOURNAL OF COMPARATIVE NEUROLOQY, VOL. 31, NO. 4 



