1^6 BIOLOGICAL LECTURES. 



Edellostoma polytrema (Girard), 1854. 



" " (Giinther), 1870. 



" " (Putnam), 1S74. 



" Stoutii (Lockington), 1S78. 



I'olistotrema dombeyi ((iill), 1S81. 



" " (Jordan, Gilbert), 1882. 



Iklellostoma forsteri. / 



" cirrhatus. ) 



" hexatrema. 



" heterotrema. 



" lieptatrema. 



I shall, for my own convenience, hereafter use the numerical 

 method of designating the varieties ; and, unless sufficient 

 reasons be brought against this style of name, I would urge 

 its adoption on the ground of convenience, to go no further. 



Iklellostoma dombeyi, 6 gills. 



'• '■ 6-7. ( Indicating the sides of the body upon 



" " 7-6. S which the respecti\e numbers occur. 



" " ID. 



" " II. 



" " II-I2. 



" " 1 2-1 I. " 



'* u j2. 



(( t< J '>_j -•^ 



" " 13-1-- 



13. 

 14. 



Physiological. 



From previous experience it seemed to me very desirable 

 that physiological experiments should be tried upon the car 

 of some vertebrate with the simplest existing ty])e, and, if 

 possible, upon an animal which lacked fins, — /. r., paired 

 appendages, which in all fishes are specially used in main- 

 taining the equilibriimi of the body. I felt that by seciu-ing 

 these conditions, we shoidd be able to get much cleanei" 

 responses or, in any case, safer results from operations on 

 -the ear, for the presence of the paired fins — especially the 

 pectoral fins — complicates the reaction to ear operations by 

 introducing into observable jihenomena mechanical factors 

 whose influences have not been carefully enough studied and 



