PROC. U.S. NAT. MUS.. VOL. 112 



BERRY AND ANDERSON PLATE 1 



Diagrammatic dorsal view ol heads "I Astroscopui y-graecum and Astroscopus guttata? 

 illustrating growth changes in shape or relative position of the Y-shaped processes of the 

 frontal bones, the posterior nostril groove and the area of skin covering the electric organs. 

 Astroscopus y-graecum: a, 4 ; mm. S.L.; c, 112 mm. S.I..; e, 14 inches total length; g, 



523 mm. S.I.. (17.5 inches total length). Jstroscupu< guttatus: B, 45 mm. S.I..; D, 98 mm. 

 S.L.; F, 12 inches total length. E and r modified from Dahlgren (1927, ftgs. 4 and 11). 

 The measurements shown in g are: a, distance from eye to rear end of posterior n stril 

 groove; b, distance from rear and of posterior nostril groove to posterior margin of skin- 

 1 1 1\ ered area. 



