65^ 



I Average 



diameter 



k of the eye 



ball, in 



m.m. 



/. Monitor (Varanus niloticus) (1) 



2. Little Gecko (Hemidactylus Brooki) (4) 



^. Emerald Lizard (Lacerta viridis) (aver.) 



4. Cobra (Naja melanoleuca) (1) 



J". Common Viper (Vipera berus) (7) 



6. Common Lizard (Lacerta agilis) (2) 



7. Slow Worm (Anguis fragilis) 



"• » 1) I) » 



9. Greek Tortoise (Testudo graeca) 



jlöOO. G. 2.440 G.' 0.0165 12.5 



4.7 0.043 



16.8 0.093 

 IhTO.O ! 0.646 



64.2 j 0.105 

 12.507 0.076 



16.252 0.039 



I 



18.9 1 0.037 

 993.58 0.360 



0.0181 

 0.0191 

 0.0098 

 0.0102 

 0.0185 

 0.0082 

 0.0071 

 0.0075 



4.1 

 5.8 

 7.0 



2.8 



Herewith the following values for r are obtained. By comparison 

 of 1 with 2:0.5476, of 1 with 3:0.5355, 4 with 5:0.5478. The 

 average for the examined Reptiles is 0.5436. 



All these valnes are again so near to 0.55 . .. or Vo, that there 

 is no doubt but the same exponent of correlation may be accepted 

 for the three highest classes of Vertebrates. Here already I point to 

 the low value of k both of the Slow Worm (Anguis fragilis) and of 

 the Snakes in contradistinction to the Lizards. 



Regarding Amphibia I have not been able to obtain entirely satis- 

 factory data for the calculation of r. The giants among these, as the 

 American Bullfrog ^Rana mugiens or Caiesbyana) and the Indian 

 Tiger-spotted Frog (Rana tigrina), reach only 5 times the size of the 

 nearest related species to be compared with. For the Bullfrog I have 

 calculated of Donaldson's^) 6 largest individuals the value of .>.' 244.4 G. 

 and of e 0.204 G. A comparison of the latter with our Waterfrog 

 (Rana esculenta), according to Lapicque's averages for s and e, gives 

 only an exponent of correlation of 0.3843. Compared with Lapicque's 

 Rana fusca (aver.) r becomes on the contiary = 0.5501. It seems 

 that the Bullfrog, at least in the organisation of the nervous system, 



d'Anthrop, I.e. p. 263), with s= 11.34 KGM affords, as not full-grown, probably 

 too high a /c (0.0268). For a "Crocodile" mentioned by Manouvrier ("Sur l'interpré- 

 talion de la quanlilé dans rencéphale". Mémoires de la Société d' Anthropologic. 

 Paris 1885. 2me Série, Tome 3, 2me fase. p. 167) of about 70 KGM body weight, 

 we find k = 0.0290. 



») Decennia! Publications. University of Chicago. Vol. X. (1902), p. 7 and Journal 

 ÜI Comparative Neurology. Vol. 8 (1898), p. 830. 



