Pomona College, Claremont, California 143 



5. How are cells related to each other (a) by neurites and 

 dendrites or fibers, and (b) by fibrils? 



6. How and where is the impulse carried? How are the non- 

 medullated fibers able to carry a definite stimulus or impulse if 

 they are not insulated? 



7. Do nerve cells act in groups, each for a special purpose, or 

 is their effect a massed one, somewhat diffuse and related to other 

 systems? Do impulses pass along definite or difuse pathways? 



8. Does the size of the animal make a difference in the com- 

 plexity of the nervous system, and is this complexity or lack of it 

 shown in the nervous system as a whole, or in the individual cells 

 which compose it? Do large animals have more nerve cells than 

 small ones? Do large animals have larger nsrve cells than the 

 small creatures? 



9. Are the conditions in the central nervous systems of inver- 

 tebrates comparable with those of vertebrates? 



10. Are the resmblances which Patton and others have seen in 

 Limulus and other invertebrates to vertebrate structures more than 

 chance resemblances, due to special adaptations, or modifications 

 of the nervous system? 



11. Is it possible to determine from the brain of an invertebrate 

 the degree of intelligence or instinct from a study of the structure? 



12. Is there any higher center in an invertebrate central ner- 

 vous system or in certain invertebrates which shows something of 

 a directive power in the life of the organism? 



13. What are the functional divisions of the nervous systems 

 of invertebrates? 



14. Are there advantages in the study of the nervous systems 

 of invertebrates over the study of the brain and ganglia of more 

 complex forms? 



15. What are the animals whose nervous systems are adapted 

 for further study of various problems? 



Some suggestions in the way of my present opinion in respect to 

 certain of these questions are as follows: 



1. In some cases it may be that simple contact is the only way 

 cells are related, but from the study of many forms I believe that 

 more intimate relations between cells by means of tibrillae are often 



