854 



largest male dogs, which weigh from 12040 to 53000 grams, mean 

 weight 27503 grams, and possess from 70 to 123, on an average 

 100 grams of brain, are compared with the 7 smallest female dogs, 

 which weigh from 6000 lo 14250 grams, mean weight 8908 grams, 

 and possess from 64 to 86, on an average 77 grams of brain, we 

 get an exponent of relation of 0.2318; i.e. very nearlj' the inter- 

 individual exponent for equal sexes of dogs, as determined by 

 Lapicque. 



i!\mong Richet's 157 dogs') twenty are stated to be female. 

 Possibly there are among the remaining dogs a few more female 

 ones, not indicated as such ; this does not make much difference 

 for our purpose. When these twenty female dogs are compared 

 with an equal number of male dogs, the body weights of which lie 

 as close as possible to those of the female dogs, these weights for 

 the two sexes together ranging from 5 to 37 kilograms, and the 

 brain weights from 53 to 125 grams, we find (always comparing 

 sets of ten) : 



between the largest cT and the smallest ^ an exponent of relation 0.3287 



,, M ,, <ƒ ,, ,. >. cT ,, M M >. 0.3374 



„ „ 5 „ „ „ c^ .. „ . M 0.2988 



„ .. S „ ,. „ 9 „ „ „ ,. 0.2899 



It is evident that the discontinuity in the transition from the one 

 sex to the other, which is so striking in the human species, does 

 not exist here. 



Of tive domestic cats, examined by Wilder'), three male cats 

 have a mean body weight of 3284 grams, and a brain weight of 

 29 grams, two female cats a mean body weight of 2410 grams and 

 a brain weight of 27 grams, from which an exponent of relation of 

 0.2310 can be calculated. 



According to L.apicque two bulls and six cows '), with mean body 

 weights of 540 and 397 kilograms and mean brain weights of 480 

 and 429 grams, give 0.3650; two rams and three sheep, with body 

 weights of 55 and 50 kilogr. and brain weights of 140 and 125 grams, 

 give 0,2064 for the exponent of relation. Also the first mentioned 



1) Charles Richet, Poids du cerveau, de la rate et dii foie, chez les chiens 

 de différentes tailles. Gomptes rendus de la Société de Biologie de Paris, T. 3, 

 9me Série Paris 1891, p. 405—415. 



') B. G. Welder. Cerebral Variation in Domestic Dogs. Proceedings of the 

 American Association for the Advancement of Science, 22nd Meeting (i873)_ 

 Salem 1874, p. 238. 



3) Bulletins et Mémoires de la Société d'Anthropologie de Paris. Seance du 

 6 juin 1907, p. 335—336 



