114 



MARINE ANIMALS OF MASSACHUSETTS BAY. 



tentacles are pointed, 

 as if to enable them 

 to work their way 

 through the mud in 

 which they make their 

 home. The pointed 

 tentacles of this genus 

 are characteristic of a 

 large group of Star- 

 fishes, and it is an im- 

 portant fact, as show- 

 ing their lower stand- 

 ing, that this feature, 

 as well as the pentag- 

 onal outline, obtains 

 in the earlier stages 



of growth of our more common Star-fishes, while in their adult 

 condition they assume the deeply indented star-shaped outline, 

 and have suckers at the extremities of the tentacles. 



Solaster. (Solaster endeca FORBES.) 



We find also among Star-fishes the same tendency to multipli- 

 cation of parts so common among the Polyps and Acalephs. 

 Our Solaster (Solaster endeca Forbes), for instance, has no less 

 than twelve arms ; it inhabits more northern latitudes, though 

 sometimes found in our Bay ; on the coast of Maine it is quite 

 common, and occurs in company with another many-rayed spe- 

 cies, the Crossaster papposa M. & T. The color of both of these 

 Star-fishes is exceedingly varied ; we find in the Solaster as many 

 different hues as in the Cribrella, which it resembles in the struc- 

 ture of its spines, while in the Crossaster bands of different tints 

 of red and purple are arranged concentrically, and the whole sur- 

 face of the back is spotted with brilliantly-tinged tiny wreaths of 

 water-tubes, crowded round the base of the different spines, which 

 are somewhat similar to those of the Astracanthion. 



Fig. 147. Ctenodiscus, seen from above : natural size. 



