REPORT OF COMMISSIOXERS OF INLAND FISHERIES. 15 



The first species is extremely abundant and is altogether too 

 well known from its depredations on the mussel and oyster beds. 

 The closely related purple star-fish is certainly very rare, at least 

 from Rock}^ Point north. Among the thousands of stars examined 

 from the oj^ster beds at Rocky Point, Kickemuit river, and other 

 localities, I have never seen a single specimen. It is, however, 

 common at Newport. If it were as abundant as the common five- 

 finger it doubtless would be equally destructive to the oyster and 

 mussel. The purple star-fish can usually be readily distinguished 

 from the more common species. It has a purple or sometimes 

 reddish color, and a softer, less rigid skeleton, and the arms are 

 more tapering. Other characters, for example the shape of the 

 minute forceps (pedicellaria) which are found among the spines 

 on the whole upper surface of the body, are of more technical value 

 in the determination of species. 



The examination of a large number of specimens of the common 

 star-fish, and of the related purple star, shows that there is a great 

 deal of variation among the individuals of the same species with 

 regard to color, shape of the arms, and size and number of spines. 

 These variations are so great that the French naturalist, Perrier, 

 made five distinct species of Asterias to include those star-fish 

 along our coast, which, according to the American naturalists, 

 L. Agassiz, Stimpson, and Verrill, belong to only two species. The 

 fact remains, however, that the star-fish of either species vary 

 greatly in form and color. The young stars whose arms are less 

 than one-half inch in length show the same variation as are seen 

 in the adults. It would be interesting from a biological point of 

 view to determine whether these variarions are due to sex, to sur- 

 rounding conditions, — food, density of the water, etc., — or whether 

 they are casual individual differences. 



The small blood star-fish, Cribrella, could not easilj^ be mistaken 

 for either of the preceding species. It is bright red, with round, 

 smooth, tapering arms. These stars are found occasionally upon 

 the oyster beds, and several were taken during the dredging ex- 

 cursion from Brown University, in the spring of 1897. 



