Lull — Functions of the ^'Sacral Brain^^ in Dinosaurs. 471 



Aet. XXXVIII. — On the Functions of the "Sacral 

 Brain'' in Dinosaurs; by Richaed Swann Lull. 



[Contributions from the Paleontological Laboratory, Peabody Museum, 

 Yale University, New Haven, Conn., U. S. A.] 



Branca, in a discussion of the fauna of Tendaguru, 

 East Africa/ makes a number of thought-inspiring com- 

 ments upon the huge sauropod dinosaurs which the 

 formation contains. Among other points he is striving 

 to account for the maintenance of their immense bulk 

 upon a possibly meagre diet by assuming digestive 

 powers of extraordinary efficiency. For this he offers 

 the following explanation: 



''One may be inclined to look for the ability to take care of 

 food solely in the stomach, intestines, or liver. However, in the 

 dinosaurs we may take into consideration something else, ^. e., 

 the 'sacral brain,' if we look upon the swelling of the spinal 

 column in the sacrum as a ' brain. ' According to Waldeyer, it is 

 indeed thinkable that the sacral brain in dinosaurs had a certain 

 independence, and cared for the functions of nourishment, 

 digestion, and procreation [italics mine], also that through a 

 particularly strong innervation it had become especially power- 

 ful, more powerful than the strongest digestive organs could be 

 without such a sacral brain. In man there appear still to be 

 traces of this, but here the sacral section of the spinal colunm 

 is completely surpassed by the brain." 



What "Waldeyer based his argument upon I do not 

 know, but the evidence which I have been able to secure 

 seemingly does not justify such a speculation. This 

 evidence is here presented. 



Dinosaurian feeding habits. 



Our assumption of feeding habits based upon the char- 

 acter of dinosaurian dentition justifies the following 

 conclusions : 



Theropoda. — These are the carnivorous dinosaurs in 

 a strict sense, with teeth which were in the main prehen- 

 sile and as such confined to the forward portion of the 

 jaws. They must have been used for rending the prey, 

 for in many instances, such as AUosaurus or Megalo- 



^ W. Branca, Die Eiesengrosse sauropoder Dinosaurier vom Tendaguru, 

 ihr Aussterben und die Bedingungen ihrer Entstehung, Archiv fiir Bion- 

 tologie, 3. Bd., 1. Heft, 1914, pp. 71-78. 



