SHALLOW-WATER STARFISHES 99 



heads. They are few in number, and are arranged in five regular 

 rows; those of the marginal row, twenty-five in number, being a 

 little smaller and more elongated than the others; median row con- 

 sisting, like the marginal row, of twenty-five spines, one to each 

 ossicle; intermediate row with only ten spines, and becoming 

 " zigzag " toward the extremity of the ray. On the disc there is 

 a regular pentagon of about ten spines, one (rarely two) to each 

 angle, and one (rarely two) at the middle of each of the concave 

 sides. No spines within the pentagon except one central one, which 

 is always present; madreporic plate within the pentagon, at the 

 periphery. Minor pedicellariae are scattered, in clouds, over the 

 dorsal surface, but there are more of the major kind on the back. 

 Papulae in groups. Diameter, four and a half inches. 



"Habitat, Puget Sound North West Boundary Commission. 

 Dr. C. B. Kennerly. This fine species is common in the circumlit- 

 toral zone/' 



The figures are from photographs of Stimpson's original types in 

 the U. S. National Museum. They were furnished by Dr. Richard 

 Rathbun. These specimens are probably immature. 



VARIATIONS. 



A purchased specimen in the Museum of Yale University, labelled 

 simply as from the " West Coast/' agrees closely with Stimpson's 

 type, except in characters due to its smaller size. Its radii are 

 10 mm. and 39 mm. ; ratio, about i : 4. The rays are high and 

 somewhat carinate. The dorsal ossicles are not numerous, rather 

 stout and broad, but have rather broad rounded papular areas; the 

 ossicles of the median row are small but prominent, each bearing, 

 near the base of the arm, two short obtuse or subcapitate spines, but 

 distally only one. Between the median and the superolateral row 

 there is a single row of fewer, larger, obtuse spines, with striated 

 ends. The superomarginals are a little longer and somewhat conical, 

 one to a plate. The pentagon of spines on the disk has usually two or 

 three spines at each angle, one or two on each side, and two on one 

 ossicle in the middle ; all these are capitate and striate. Madreporic 

 plate raised, wart-like, with fine radiating gyri. The under side is 

 nearly as described by Stimpson. 



The adambulacral spines are uniserial, very slender, terete, tapered, 

 subacute. The synactinal plates are small, rounded, and prominent, 

 extending to about the distal fourth of the ray, each bearing a spine 

 like the inferomarginals, but rather smaller. The latter, which 



