XIV FINAL EXERCISES ON COMPARATIVE ANATOMY 



A. COMPARISON OF CROSS-SECTIONS 



Make diagrammatic cross-sections through Hydra, Planaria, earthworm, 

 and frog, putting in all the layers of the body. Color ectoderm blue, mesoderm 

 red, entoderm yellow, peritoneum and mesenteries green. Indicate epithelial 

 layers by crosslines at right angles to the surface; connective tissue by solid 

 shading, muscles by diagonal lines, skeleton by dots. After finishing, these 

 diagrams, study them and be sure that you understand thoroughly what layers 

 correspond in the four animals, and in what important ways the sections differ 

 from each other. 



B. COMPARISON OF FUNCTIONAL SYSTEMS 



Make a table as follows. Rule off a page with vertical and horizontal lines 

 so as to make a number of vertical and horizontal columns. At the left, in the 

 spaces between the horizontal lines, write the names of all the animals studied 

 in this course, beginning with the amoeba and ending with the frog, in their 

 proper phylogenetic order. At the tops of the vertical columns, going from 

 left to right, write the names of the systems in the following order: digestive 

 system, muscular system, nervous system, reproductive system, excretory 

 system, circulatory system, respiratory system, skeletal system. In the ap- 

 propriate spaces opposite the names of the animals, write in very briefly 

 whether the animal has such a system and if so what it consists of. The 

 table when finished will illustrate the gradual increase in numbers of systems 

 and complexity of each system through the animal kingdom. Note that a 

 system consists of parts set aside for the performance of specific functions. 

 Thus the amoeba respires but it has no respiratory system, that is, no structures 

 for that purpose. 



126 



