EXERCISE 105 (Continued) 



Go over the list of organs named and place the letter a after the first one and after all the others 

 that are homologous with it ; then place the letter b after the first one not yet marked and after each one 

 that is homologous with it ; then mark a third group with the letter c ; and- so on until all are checked off. 



Go over the list again and mark with a capital A the first one and all that are analogous with it ; 

 then mark with a letter B all that are analogous with each other but not with the first group ; and so on. 



Questions. 1. What are the greatest differences that you have observed between organs that are 

 homologous ? 



2. What are the most diverse organs that you have observed as having a similar function ? 



3. What is suggested by a study of analogies and homologies concerning the plasticity of protoplasm ? 



[113] 



