22 GENERAL BIOLOGY. 



8. The cuticle. 



With forceps strip off under water the cuticle from 

 the lateral and ventral aspects. Mount it in 

 ivater on a slide, and examine first ivith a low 

 and then ivith a high power. 



With the low power observe : 



(a) The tubular processes of the cuticle torn 



from the setae-sacs. 

 With the high power observe : 



(b) The thin transparent membrane not com- 



posed of cells. It is traversed by deli- 

 cate lines and perforated by minute 

 pores. 



9. Before leaving the anatomy of the earth- 



worm see a demonstration of a nephridium 

 from a recently chloroformed worm. 

 10. Make a drawing ( X 5) of an egg-capsule. 



D. MICROSCOPIC STRUCTURE OR HISTOLOGY. 

 I. Prepared transverse section. 



For detailed directions see "General Bi- 

 ology," Sedgwick and Wilson, second edition, 

 1895, pages 91 to 95 inclusive. 

 Make a diagram shotving in outline the different 



regions of the section. 

 Sketch accurately, much enlarged, a portion of the 



section a few cells in ividth. 



Make an accurate sketch of the cross-section of the 

 ventral nerve-cord. 



