235 



are indicated on the abscissa, the brain weights in gr. on the 

 ordinate. The points Z, F, F, and L lefer to the averages of those 

 weights of the species Canis zerda, Canis vulpes, Oanis fainiliaris 

 and Canis luj)us. The relation of brain weight and bodj weight in 

 these species of the genus Canis is heie graphically represented by 

 the full exponential curve Z V L, defined by the equation ^ = 0.41 

 P°/», and by the point F, whose position is defined by the 

 equation 89 = 0.385 x 18000Vs*. In Fig. 3 the same relation is 



Poo 1000 3.0 



Loq. lOO 



Dg. 10 



.7 

 .6 

 .5 

 .4 



3 

 .2 



I 



5.0 



9 



I .0 

 30 



.3 .t, .5 .fa 



Cocj 10000 



8 .9 50 

 lOa.lOOOOo 



Fig. 3 



represented by the full logarithmic line, a straight line with which 

 the, lines of genera and species with other cephalisation would run 

 parallel. 



An entirely different exponent of relation, viz. about 1/4' '-O- less 

 than V18, half the value of the exponent holding from species to 

 species, was found on comparison of large adult individuals of one 

 and the same species by Lapicque for the Domestic Dog') in 1898, 



^) L. Lapicque, Sur la relation du poids de l'encéphale au poids du corps. 

 Gompies rendus de Ia Société de Biologie. Paris 1898, p. 63. 



