Donaldson, Nervous System of the Frog. 325 



The bottles containing the segments of the legs were then 

 weighed separately. Next each segment was removed from the 

 bottle and the bottle itself freed from any fluid that had collect- 

 ed in it. The skin, together with the bone (or bones), sepa- 

 rated as completely as possible from the muscles and tendons, 

 were returned to the dry bottle, which was weighed for the sec- 

 ond time. 



The difference between the first and second weighing gave 

 the weight of the muscles of the respective segments. 



The length of the leg bones was then determined. This 

 measurement was made while the bones were fresh and moist, 

 since they shorten on drying. 



VIII. Explanation of the Entries in Table 7. 



From this table all derived numbers such as ratios and 

 percentages have been purposely excluded. The derived num- 

 bers appearing in the body of the paper are, however, based 

 on the records in this table, and can be verified by means of 

 them. 



As will be seen by examining the table, the various weigh- 

 ings were in centigrams or milligrams, as the case demanded, 

 and lengths were taken in millimeters or tenths of a millimeter. 



To facilitate the understanding of the Table 7, an explana- 

 tion of each of the entries there found is added. 



Number. 



The number is given solely for the purpose of identifying 

 the record. 



The letter following it indicates the locality at which the' 

 frog was captured. 



A. Lake Como — near Williams Bay, Wisconsin. 



B. Fresh water Pond — near Oconomowoc, Wisconsin. 



C. Several Ponds — near North Judson, Indiana. 



* Following the letter designating locality indicates that 

 the record has been used in Chart i. 



Sex. 



M. Male. 

 F. Female. 



