REGENERATION IN PLANARIA 



(Materials: large pipette, watch glasses, pond or cistern 

 water.) 



Classification : Phylum Plathelminthes, Class Turbellaria, 

 Order Tricladidea. 



A fresh-water flat worm will be given you in a watch glass 

 containing pond water. Make out the characteristics of structure 

 and movement. 



Make a 100 mm. drawing across the top of a page showing 

 as many of the following parts as possible: (i) general body 

 shape, (2) the pharny.v is a cylindrical structure near the middle 

 of the body (usually the pharnyx is retracted within the body 

 except when food is being taken) ; (3) the mouth is at the pos- 

 terior free end of the pharnyx, (4) the intestine consists of three 

 main branches leading off from the anterior end of the pharnyx, 

 (5) the eye spots, (6) the sensory lobes, earlike structures on the 

 sides of the head. 



The worm is to be cut into three pieces of as nearly equal 

 size as possible. One transverse cut is to be in front of and the 

 other behind the pharnyx. Sharpen scalpel on knife stone. While 

 the worm is crawling along on the bottom of the watch-glass 

 place the point of the scalpel against 'the bottom of the dish at 

 one side of the worm. With a fairly quick rocking movement 

 roll the edge of the knife across the body of the worm, thus 

 severing the body with one clean cut. 



On your first drawing indicate with broken lines the planes 

 of the cuts. Make outline drawings of the three parts imme- 

 diately beneath the drawing of the entire animal, placing the parts 

 in the same relative positions. Next to these drawings record 

 the date of the operation. 



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