40 INLAND FISHERIES. 



the stuitisli are dispersed while in the free-swimming" hirval condi- 

 tion. We M'ill refer to this question again in Chapter X. 



MODE OF LIFE. 



III. WAut is tlic inet/iod of locoiiiotwn ? {It is jjossib/e that 

 sohie harrier iiiiglit he arranged that loould Ihult, if not prevod, in- 

 vasion.) 



The starfish crawls or glides over submerged surfaces by means 

 of the very numerous "suckers," or feet, which protrude from the 

 furrows on the under side of the arms. 



Small stars, one-half inch or less from tip to tip, are frequently 

 seen, ventral side uppermost, moving along with their suckers 

 reaching to the surface of the water. This performance can be 

 carried on only wdien the water is very quiet, and is not often ob- 

 served outside the aquarium. The buoyancy of the water and 

 the great number of sucking feet enable the animal to crawl over 

 the softest silt and the smoothest hard surfaces with ease, while 

 the remarkable suppleness of the body enables it to get through 

 incredibly small crevices. Beside this ordinary mode of locomo- 

 tion, another peculiar method has been accredited to the starfish 

 by many : namely, that of clinging together in great clusters and 

 rolling along the bottom with the tide. 



For the purpose of testing the ability of starfish to creep over 

 soft surfaces, vaseline was smeared thickly on a vertical glass 

 plate and on the under side of a hf)riz;ontal glass plate. These 

 plates were submerged in the aquarium with the starfish which 

 measured two or three inches from tij) to tip. The animals were 

 observed to crawl over both these surfaces with no apparent diffi- 

 culty. Paraffine was used in the same way and with the same Re- 

 sult. It Avould appear, therefore, that, submerged surfaces, though 

 ever so soft or slip])er3^ would not be effective barriers against 

 the invasion of starfishes. 



As was stated in the last report, starfishes will not crawl out of 

 the water, nor even i)r()tnide an arm above the surface. They 



