DISSECTION OF HOLOTHUBIANS. 



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 Lily. 



