654 



that of Salamanders and Newts, where the latter, which live 

 in water, have however lower cephalisation than the Landsala- 

 mander. In general the vahie of k does not differ much from that 

 of Reptiles. 



If now we find in the lowest class of Vertebrates, the Fishes, 

 for r the same value as for the three highest classes, then it is 

 certain that also in (he Amphibia, which rank between them, the 

 same relation exists between weight of the body and weight of the brain. 



Of the following evidence regarding Fishes the greater part has 

 been borrowed from Welcker-Brandt ^). 



When comparing each time two, the nearest affined species, the 

 following values for r are found: 1 with 2 • 0.5633, 7 with 3: 0.5522, 

 4 with 5: 0.5201, 6 with 2: 0.5949, 7 with 8: 0.666J . 



With the exception of the last, to which I shall revert 

 afterwards, these values are also all near to 0.55 . . . The average 

 of the four is 0.5576. 



Eels (Muraenidae) excepted, the comparatively high values of 

 k, in which most Fishes equiil even the examined Reptiles, are 

 striking. In the low value of k in the Eels we find a similar pheno- 

 menon, the probable cause of which I shall indicate afterwards, as 



1) L. c, p. 59-61. There 3 more perches. The statements for them deviate 

 however so much from what may be admitted as normal for tliis species, that 

 they cannot be used separately for truslwortliy calculation of r. Compared with 

 Ihe 2 sticklebacks they give for r values ranging from 0.437 to 0.644. The 

 average of 4 comparisons is 0.525. 



2) E. Crisp in Proceed. Zool. Soc. London. Part 24. (185(5), p. 106. 

 '^) L. Lapicque, Bull, et Mém. Soc. d'Anthrop., 1 c. p. 263. 



