DISSEOTION OF HOLOTHURIANS. 137 



Laboratory Work. — The Holothurians are easily dissected by cutting 

 the body open longitudinally, and pinning the specimen down In a 

 -dissecting-pan, with wax on the bottom for holding the pins. The 

 -calcareous plates can be extracted from the body- walls by being placed 

 in a solution of potash and mounted in balsam as microscopic objects. 



Bncrinus or Stone LilT- 



