4 VERRILL 



The great abundance, size, and voracity of these Pacific starfishes 

 will always be a great hindrance to the cultivation of oysters, mus- 

 sels, etc., on that coast, except, perhaps, where the water is dis- 

 tinctly too brackish for starfish life. 



Fortunately for the mollusca, at least, most of the larger littoral 

 starfishes are more or less cannibals. When opportunity occurs, 

 they do not hesitate to devour each other. 



From the stomach of a large ten-armed Solastcr, I have taken the 

 half -digested ray of an Asterias that must have been a foot across 

 when living. An inch or two of the ray still protruded from the 

 mouth of the Solaster, for it was much too large to swallow entire. 



The various kinds of starfishes that inhabit rocky shores, clinging 

 to the rocks, have large numbers of strong, muscular sucker-feet, 

 each tipped with a perfect sucker for adhesion. In the ordinary 

 five-rayed kinds, six to eight inches across, there will be four close 

 rows of such suckers the whole lengfth of the ray, perhaps 200 to a 

 ray; or 1,000 on the five rays. 



In the case of the many larger five-rayed and six-rayed kinds, two 

 feet across, the number of suckers may be 4,000 to 8,000 or more. 



How many there are on the big twenty-rayed or twenty-four- 

 rayed star of that coast, which becomes over thirty inches across, and 

 has the suckers mostly crowded into four rows, on each ray, nobody 

 knows, for apparently nobody has had the patience to count them. 

 Probably there may be more than 40,000. I refer to the great Pycn«- 

 podia or " sun-star." (See pi. xxix.) 



Such starfishes are able to open an oyster or mussel by a long and 

 steady pull with these suckers, while the rays are wrapped around 

 the victim. All such starfishes can evert the large, loose, bag-like 

 stomach and wrap it around its prey till digestion is completed, 

 if it be too large to swallow entire. But the mouth is also 

 very extensible and dilatable, so that they can swallow objects sur- 

 prisingly large. I have often taken sea-urchins an inch or more in 

 diameter with the spines nearly all in place, from the stomachs of 

 starfishes of no more than ordinary size. 



ACTIVITIES OF STARFISHES: MIGRATIONS; RATE OF TRAVEL. 



Although most starfishes, as ordinarily seen in life clinging to 

 stones, etc., appear very sluggish and slow in their motions, they 

 are really able to travel to considerable distances and undoubtedly, 

 in some cases, make migrations of considerable extent, either in 



