No. 3-] ACUTE VISION IN VERTEBRATES. 459 



In the animals which I have examined the space for the 

 observer is left blank, excepting when the species has been 

 previously examined, in which case I have inserted (S) after 

 the name of the first investigator. 



In the following tabulation I have adopted the form of 

 Chievitz, and have endeavored to present the results of all 

 investigators up to the present time. Some results have 

 necessarily been omitted, as the investigators in their descrip- 

 tions have given only the common name and not the species of 

 the animal. 



