SHALLOW-WATER STARFISHES 75 



middle of the ray. Probably there are at least four rows of inter- 

 actinal ossicles. 



The dorsal spines, as stated, are small, mostly subacute, and 

 arranged in a distinctly areolated or reticulated pattern, many of 

 them forming regular transverse or oblique rows or combs on the 

 reticulating ossicles; but they differ rather more in size than indi- 

 cated in the original description, some of them being much 

 smaller, more slender and very acute. But they are far more uni- 

 form than in P. ochraceus. They do not form a definite median row, 

 The dermal minor pedicellariae are numerous. The dorsal, sessile, 

 dermal major pedicellariae are often larger than the spines on the 

 dorsal surface, especially at the interbrachial angles above, and also 

 below, and along the lateral channels. The actinal spines bear thick 

 clusters of minor pedicellariae on their outer sides. 



VARIATIONS. 



A specimen of this species from Malaspina Inlet, coll. G. M. 

 Dawson, 1885, received from the Geological Survey of Canada 

 through J. F. Whiteaves, agrees well with the type in most respects, 

 but it has distinct radial bands of small spines. Radii, 28 mm. and 

 no mm.; ratio, 1:4; but the dried specimen is considerably flat- 

 tened, due to imperfect preservation. 



The dorsal surface is very irregularly reticulated; the numerous 

 small spines have a tendency in many parts to form rather long 

 transverse or oblique rows. Most of the spines are short and blunt, 

 or subacute, but some of the smaller ones are slender and very acute. 

 Minor pedicellariae of very small sizes are exceedingly abundant, 

 both in wreaths around the bases of the spines and on all the inter- 

 mediate surface. The superomarginal spines form a somewhat 

 irregular band of small spines, scarcely larger than the dorsals, sev- 

 eral standing on each ossicle. The inf eromarginal spines are similar, 

 a trifle longer, blunt, and mostly striated distally, two often standing 

 on one plate. The interactinal spines, which form three or four 

 rows proximally, are similar in form, but increase in size toward the 

 grooves. The adambulacral spines are long, slender, and regularly 

 tapered. The giant pedicellariae occur mostly on the interradial 

 areas and lateral channels. Some of them are stouter than the inter- 

 actinal spines, but shorter. They are usually stout and blunt, very 

 obtusely conical or blunt wedge-shaped, with slightly denticulate 

 tips. The ambulacral pores are crowded into eight rows proximally. 



