ECHINODERMS 69 



The label, written in pencil or carbon ink on good grade paper 

 that will not dissolve in the preservative, should record place and 

 date of capture and the name of the collector. As some of the 

 coloring matters of leeches are freely dissolved or altered by the 

 fixing and preserving fluids, it is desirable also, if practicable, to 

 record the living colors on the label. Every additional ecological 

 or other fact added to the record increases the value of the 

 specimens. A number of specimens of each kind should be 

 collected. 



ECHINODERMS 



This group includes the sea urchins, starfishes, brittlestars, 

 crinoids or featherstars, and holothurians or sea cucumbers. Take 

 samples of the larger ones but direct attention mainly to collect- 

 ing the smaller and less conspicuous kinds, which are less well 

 known. They are also easier to preserve and occupy less space 

 in shipping. 



Sea urchins. — These are more or less common everywhere, from 

 between tide marks down to great depths. There are three main 

 types: Globular, with more or less long and numerous spines; 

 oval, with short, or mixed short and long spines; and flat, solid 

 ones with very short spines, usually called sand dollars. The 

 globular ones live on rocky or hard bottom, or among seaweeds, 

 and are often common in tide pools. Some bore holes in rock, 

 in which they live. A few hide in holes or dark places during 

 the day, coming out at night. The oval ones live either exposed 

 on soft or hard bottom or, like the sand dollars, burrow beneath 

 the surface of sandy mud. 



Specimens preserved in alcohol are preferable, but because of 



