extension. Notice the linger-like extensible and retractile poim>, 

 covered with a sort of hood. Ho\v many of the points are there? 

 Are they ciliated? Observe if possible that the whole structure is 

 Mipplied with much blood, which circulates through it. In some 

 species the points are much longer, extending out like ringers. 

 What is the function of this structure? \Yliy is it ciliated? Why 

 is it so well supplied with blood? Draw the structure carefully. 

 c. Xephridia are present in Dero, but are not favorable for 

 .^ttldy. 



255. Study, if opportunity is given, the living nephridium of the 

 earthworm. Observe especially the ciliary movements in the funnel. 

 Distinguish funnel, secretory portion, and reservoir. Observe the 

 ciliary movement within the secretory portion. Observe also, if it 

 is possible, the blood vessels covering the nephridium. Examine the 

 figures in Beddard's Monograph of the Oligochaeta (or copies of 

 these ) ; note in these the blood vessels. 



E. CRUSTACEA. 



256. Study the respiratory and circulatory processes in Daphnia 

 Where does respiration occur? How is the respiratory current 

 produced? (Use India ink if necessary.) Observe the beating of 

 the heart, and the circulation of the blood. See the movements of 

 the blood corpuscles in the head, appendages, etc. By figure, dia- 

 gram, or description, indicate the external (respiratory), and in- 

 ternal (circulatory) currents. What uses do these currents serve? 



Can you see the alimentary canal in Daphnia? If so, sketch 

 or describe. 



257. Study, if opportunity is given, the respiratory current, by 

 means of India ink, in a crayfish or crab. Where does it occur. 

 and how is it produced? Examine in a preparation the structures 

 producing it. Examine also the gills. Observe that they are simply 

 expansions of the body wall, that have taken a complicated form. 

 Compare them with a figure on the chart, showing their relation 

 to the blood vessels. Draw one of the gills. 



2^8. Examine, and describe, if there is opportunity, the respira- 

 tory organs and respiratory movements in Limulus. 



F. IXSI-:CT. 



260. Examine and draw the respiratory organs of an insect larva. 

 In what fundamental way do they differ from the other respiratory 

 organs we have studied ? 



G. FROG. 



261. Examine the alimentary canal of the frog, and identify the 



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