WEST INDIAN STAEFISHES 



25 



Stephanasterias Yerrill, Envision Genera and Species of Starfishes, p. 222, 

 1899; North Pacific Starfishes, op. cit., p. 146, 1814a. 



Small autotomous starfishes, commonly found with five to nine 

 unequal rays, due to incomplete replacement and regulation of 

 rays after division. Two or three longer rays, and three or four 

 shorter ones are common forms. When fully mature, often reg- 

 ularly six-rayed. 



The whole surface is thickly covered with minute thorny 

 spinules, placed in clusters on the plates, and longer on the under 

 side and margin. 



The median-radial and marginal rows of plates are usually 

 distinct, with wide plates, closely imbricated radially. The sev- 

 eral dorsolateral rows have the plates small, short, and relatively 

 wide, irregularly arranged, but with longitudinal rows of papular 

 pores between them. 



The infer omarginal and interactinal plates form regular, close, 

 longitudinal rows. 



The adambulacral spines are slender, two to a plate, or alter- 

 nately one and two. Papulas are isolated or in small groups. 

 Both kinds of pedicellariae are present. 



Perrier changed the name of this genus to Nanaster, because 

 he erroneously assumed that Stephanasterias had been preoccu- 

 pied by Stephanaster Ay res. The two names are distinct and 

 differently derived. 



Stephanasterias gracilis (Per.) Yerrill. 



Asterias gracilis Perrier, op. cit., p. 4, 1881 ; Nouv. Arch, du Mus., vi, p. 

 204, 1884. 



Stephanasterias gracilis Verrill, Trans. Conn. Acad. Sci., vol. x, p. 223, 

 1879; Starfishes N. Pacific, p. 146, 1914a. 



Plate ix; figures 2-2c. 



Disk small; rays slender, variable in number, commonly six. 

 The species is autotomous, and the rays are often unequal. 



The dorsal surface is closely covered with numerous nearly 

 uniform minute, slender, subdiaphanous spinules, several on each 

 plate. The marginal spines are larger, flattened and enlarged 

 distally, mostly with a blunt and thorny tip, and more or less 

 hyaline. 



The adambulacral spines are two to a plate, shorter and much 



