PRACTICAL STUDY OF LUMBRICUS. 169 



leaves, meat, moistened paper, fat, etc. At night the worms may 

 be seen in the act of eatine;. 



C^ 



7. If practicable, study by night the habits of worms in their 

 natural homes, with the aid of a reflecting lamp or lantern. 



8. If worms be kept in coniinement in May or June they 

 may easily be observed in the act of copulation, and will lay 

 numerous eggs. 



D. Dissection. (See Appendix.) 



1. Pin out and lay open, under 50^' alcohol, a freshly-killed 

 worm, and make out the general arrangement of 



a. Body-wall, alimentary canal, dissepiments, ccelom. 

 l>. Dorsal vessel, circular vessels. 



c. Testes, seminal vesicles. 



d. Nephridia. 



e. Make a sketch showing these parts. 



f. Dissect away part of the alimentary canal behind the 



clitellum, and observe the ventral nerve-chain below 

 it ; also the sub- intestinal vessel. 



g. Dissect out the alimentary canal, make out all its dif- 



ferent divisions ; lay open the stomach-intestine from 



the side, and observe the typhlosole, p. 127. 

 h. Examine with ^-inch objective the chloragogue-cells 



mounted in water. 

 i. Examine likewise the contents of the calciferous glands, 



run in dilute acid, and note the effect. 



2. Take a fresh specimen and work out the circulatory sys- 

 tem. 



a. Study the coelomic fluid with the microscope Q~inch 



obj.). 

 5. Trace out the dorsal vessel to its anterior end. 



c. Examine the circular vessels as follows : 

 a. Of the stomach-intestine. 



ft. Of the gizzard and crop. 



y. The aortic arches. 



8. Branches to the calciferous glands. 



d. Make out the sub-intestinal vessel and compare its rela- 



tions behind the gizzard, in the crop-region, and in 

 the oesophageal region. 



e. Cautiously chloroform a very large worm, pin out 



under normal fluid, cut open dorsally with sharp 



