724 



poids, in this respect '), — facts (hat have led to speculations 

 about uncommonly great intelligence of tlie Whales — of the compara- 

 tively highly cepbalised Crocodiles, and of the class of the Fishes, 

 which in general are not inferior to the Reptiles, as far as the 

 quantity of brain is concerned, of all these problems the solution 

 is now obvious ^). The proboscis of the Elephant, which plays a pro- 

 minent part in the animal's life, is not only strong and agile, but 

 also provided with very voluminous muscles. That of the Asiatic 

 Elephant measures 2 meters for a length of the body of SVj meters. 

 Quick strong muscles move the long tail of the American Apes 

 mentioned, which muscles are of still greater service to these animals 

 than those of their hands and feet. But also their arms and legs 

 are very long in comparison with the body, especially for A teles, 

 which owes its popular name of Spider-Monkey to this, and they 

 consequently contain a large mass of muscles. The Whales have 

 an exceedingly quiok and strong motor apparatus in their long body 

 for the tail, which admirably like a ship's screw propels the gigantic 



1) Judging from not yet full-grown animals, some investigators have assumed 

 somewhat too great ceplialisation. Thus the Seal is not full grown with I2V2 kg- 

 body weight (Louis Laptcque, Sur le poids encéphalique des Mammifères amphi- 

 bies. Bulletin du Muséum d'liistoire naturelle. 1912, N*^. 1 p. 2). An adult female, 

 examined many years ago by E. H. Webfr (Ueber den Bau des Seehunds, Phoca 

 vitulina. Verhandlungen der Kön. Sachsischen Gesellschaft der Wissenschaften zu 

 Leipzig. Math.Phys. Glasse. Jahrgang 1850, p. J 08), however somewhat emaciated 

 in captivity, weighed as much as 43.11 kg. The animal possessed 266.5 grams of 

 brain, from which a coefficient of ceplialisation k = 0.6766 can be calculated. Of 

 a female Otaria californiana, which had lived in the Amsterdam Zoological Gardens 

 since 1902, and was already fully adult at the time, the body weight was 74 kg., 

 the weight of the brain 374.5 grams, at its death in Nov. 1913, from which 

 k = 0.70:25 may be calculated. The weight of the body of this animal, too, must, 

 indeed, have been somewhat higher in its healthy state. Accordingly the calculated 

 coefficients of ceplialisation are decidedly somewhat higher than normal for both 

 Pinnipeds. 



As regards the Whales, we may refer to the weight of a Balaenoptera sulfurea, 

 22.5 meters long, viz. 63 Am. tons, i. e. 64000 kg. (according to determinations 

 by Lucas inaccessible to me), which is mentioned in Vol. 12, p. 503 of the fourth 

 edition (1915) of Brehm's Tierleben. The brain, freshly removed, of a Balaenoptera 

 musculus, 18.8 m. (=60 Norwegian feet) long, weighed 6700 grams, according to 

 G. A. GuLDBERG (Korhandlingar i Videnskabs Selskabet i Christiania. Aar 1885. 

 Christiania 1886, p. 128). Assuming uniformity with the other Balaenoptera species, 

 a body weight of 37385 kg. is found for the latter, and in connection with this 

 a cephalisation coefficient of 0.3841. 



2) The significance of the influence of the organs of hearing, touch and other 

 organs of sense on the quantity of the brain of these Vertebrates is, however, 

 not slight either. 



