ECHINODERMATA 85 



at times, probably due to an increased salinity 

 caused by drought, they become very abundant. 



The usual number of rays of this starfish is five; 

 however variations from one to eight are occasion- 

 ally found. Starfish possess the power of regenera- 

 tion — that is if an arm is injured or broken off, it 

 will usually grow back again. The new arm may be 

 very small or rudimentary, thereby accounting for 

 numbers less than five ; or, two arms may grow in the 

 place of a single injury, thereby causing freaks of 

 six, seven or eight arms. 



Asterias vulgaris Verrill (Northern Starfish) 



Common along the northern coast from Labra- 

 dor to Massachusetts. In Long Island Sound it is 

 less common than the above species (A. forbesi) and 

 is found only in deeper water. Off New Jersey it is 

 usually larger than the above and lives in deeper 

 water, although the two are not infrequently found 

 in the same association. 



The following key 1} will distinguish the com- 

 mon starfish (A. forbesi) from the northern starfish 

 {A. vulgaris), although they are very closely related 

 and should probably be regarded merely as varieties 

 of a single species: 



Rays blunt at the ends; skeleton quite firm; spines 

 scattered, pedicellariae (Small scissor-like 

 spines) near ambulacral grooves short and 

 broad; madreporic plate usually orange. 

 A. forbesi 



! ) W. R. Coe: The Echinoderms of Connecticut. Conn. Geol. and 

 Nat. Hist. Surv. Bull. 19 p. 59 (1912). 



