6O R. R- HUMPHREY. 



TABLE I. 



LENGTHS OF DESMOGNATHUS MALES FROM STREAMS ON TURKEY HILL, 



NEAR ITHACA. 



Arranged in groups on the basis of the type of testis. These types, listed 

 in first column, correspond in number with the types illustrated in chart I. 

 The one animal with testis of five lobes is not included in this table; since 

 it had suffered the loss of a portion of its tail, its length could only be 

 estimated. 



that is, with testes of two complete lobes have reached practically 

 their full size, since after this, if we disregard the three animals 

 representing stages 13 and 14, there is but slight upward or down- 

 word shifting in the level of the curve. Hence the maximal size 

 may be attained when the testis is at stages 5 to 9, but the number 

 of lobes may continue to increase for some time before checked by 

 the running out of the anterior lobe at the cephalic end of the germ- 

 cell cord. If the correlation were merely one of size rather than 

 of age, one would expect a curve of quite a different type a curve 

 continuing upward in the same direction as the portion i to 5. 

 This portion of the curve, incidentally, shows the correlation of 

 size and lobe number in the sexually mature but growing male ; 

 after full size is attained lobe number still increases, and the last 

 half of the curve maintains a rather constant level. 



Graph A is based upon animals taken largely from streams on 

 Turkey Hill, about three miles from Ithaca. The animals of these 



