T 1 1 1 1 T 



I I I r 



T 1 1 1 1 r 







+° 



■f 



40 



o 



•o 



+ 



^ 



5^0 



_J^%»ij- 



X o 



X o 



3 

 J L 



Wave-length (m//) 

 ? I.I 



i I I I I I I 1 



M I I I I I I I I I I il il 



8 § S ? I § 



J__J ' ■ ' ' I ■ ' ' ' 



8 9 3 8 



M I I III I t hi 



ihhltl + 



-J ■ I . I I I I I ■ I I T ■ I iji . I ■ I ■ I I i.iiT.ni.i.i.i o 



I I I I I I I I I I t I I I I I I I'l t I 1 I I I lililililililililtl X 



30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 x10> 

 Reciprocal wave-length (cm.-') plus a constant 



Fig. 6.10. Comparison of the difference spectra (frequency abscissae) 



of the same four visual pigments as in Fig. 6.9. The spectra have been 



shifted along the axis of abscissae so that their maxima coincide with 



that of pigment 467. 



(Darmall, 1952a) 



