224 SYMBIOSIS 



to Symbiosis, and being more directly connected with the brain, 

 was destined to become the predominant partner. 



Once again we meet with the food factor in connection with 

 the " recession of the snout region," and we are told : 



It may be said on broad lines that throughout the whole of the animal 

 kingdom the mouth parts show a development depending upon the nature 

 of the animal's food and the method of taking it. If it is the hand which 

 becomes the grasping organ, the mouth and the anatomical structures 

 connected with it need no longer be developed in any special way to carry 

 on this function. The food-grasping power of the primate hand renders 

 unnecessary the development of grasping lips and a long series of grasping 

 teeth. Again, the fact that the food once grasped by the hand is conveyed 

 by the hand to the mouth renders the mouth and its associated parts 

 merely an organ for dealing with food already grasped and carried to it. 

 A mouth merely adapted for the reception of food already grasped and 

 brought to it is a structure very different from a mouth adapted for the 

 purposes of reaching out for food, seizing the food so reached, an 

 subsequently dealing with it. (Italics mine.) 



Everything depends upon the "if," and the " if " evidently 

 depends upon the appetites of the creature. It was admitted 

 by Darwin in the case of the short -snouted, tree-climbing vege- 

 tarian lizard, the Amblyrhynchus of the Galapagos Archipelago, 

 that such and similar short-snoutedness amongst tortoises, many 

 of which feed on fruits and berries, depended upon " herbivorous 

 appetites." The essential condition of progressive anatomy is 

 satisfactorily fulfilled only with symbiotic cross-feeding ; and 

 this is entirely omitted by Prof. Wood Jones. As, however, the 

 teeth are referred to, it is as well again to point out that Carni- 

 vorism could never at any time have produced the desirable 

 development. It was reported in Nature, 30.5.18, that there 

 is a remarkable uniformity in the Anatomy of flesh-eating 

 Dinosaurs of Mesozoic times, whether they are early or late, 

 small or gigantic. They all had large hindquarters for bipedal 

 walking, a long tail, very small mobile fore-limbs, and a more or 

 less regular series of sabre-like teeth. 



No one would believe that from such a carnivorous Dinosaur, 

 though it walked on its hind-legs, and though even possessed of 

 mobile fore-limbs, any progressive evolutionary development 

 was to be expected. The shape of its teeth alone, as determined 

 by the animal's feeding habits, would have precluded such 

 development. 



(True, Sir E. Ray Lankester is of opinion that it is now 



: 



