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6. Examine the buccal cavity, noting the Y-shaped oral aperture, and the 



toothed ridges which lie on the inner sxirface of the three lobes formed 

 by the strong buccal muscles. 



7. Eemove one of the toothed ridges, examine (low power), and sketch. 



8. Advanced students should prepare and 



(1) Examine (low power), and afterwards sketch transverse sections — 



(i) Through the middle of the body, showing (a) cuticle ; (S) epider- 

 mis and dermis, containing capillaries and simple glands ; (c) 

 external circular, longitudinal, internal circular, radiating and 

 dorso-ventral muscular fibres; dorsal, lateral, and ventral blood 

 vessels; and the nerve cord or ganglia ; (d) the stomach and its 

 diverticula ; («) the nephridia, testes, and vasa deferentia. 



(ii) Through the anterior end of the body, noting (a) the ocelli, 

 closed capsules containing large -transparent cells ; (6) the 

 nerve cells of the supra-oesophageal ganglia ; (c) the cup-shaped 

 glands in the epidermis. 



(2) Examine (high power) (a) one of the ovaries teased in salt solution, 



and sketch several ova ; (&) one of the testes prepared in the same 

 way, and draw the spermatozoa ; (c) one of the ganglia teased in 

 carmine or picro-carmine, and sketch the ganglion cells. 



