REGENERATION IN PLANARIA 



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

 water.) 



Classification : — Phylum Plathelmiuthes, Class Turbellaria, 

 Order Tricladida, 



A fresh-water flat worm will be giA^en yon in a watch glass 

 containing pond water. Make out the characteristics of struc- 

 ture and movement. 



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

 as many of the following parts as possible: (1) general body 

 shape, (2) the pharynx is a cylindrical structure near the middle 

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

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

 terior free end of the pharynx. (4) the intestine consists of three 

 main branches leading off from the end of the pharynx, one 

 anteriorly and two posteriorly, (5) the eye spots, (6) the 

 sensory loles, ear-like 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 pharynx. 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 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 immed- 

 iately 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. ^ 



See that the watch glass is carefully covered. Change the 

 water at each laboratory period. Make observations on struc- 



6G 



