90 VERRILL 



are short and thick, but slightly compressed and notched at the 

 extremity. Diameter, two feet. Taken in Tomales Bay, by Mr. 

 Samuels." 



Large photographs of the type, which is in the U. S. National 

 Museum, have been furnished by Dr. R. Rathbun, for reproduction 

 in our plates. Dr. Stimpson's description was very incomplete, for 

 he scarcely described the ventral side at all. 



The disk is rather large and the six rays taper rapidly to rather 

 acute tips. They are variously bent, and wrinkled, indicating a 

 rather weakly reticulated dorsal skeleton. The radii are about 

 73 mm. and 304 mm. ; ratio, about i : 4.75. 



The adambulacral spines are rather small, slender, compressed, 

 crowded, and stand in a single row, one to a plate; they are much 

 smaller and shorter than the crowded ventral spines. The latter 

 form about eight close rows proximally, but these decrease to four 

 or five at the distal third of the rays. They differ much in form. 

 Those nearer the adambulacrals are partly fusiform and sometimes 

 subacute, but more often flattened and subacute at the tip ; those of 

 the middle rows are stouter, either blunt, clavate, or flattened ; those 

 of the outer rows are still shorter and stouter, with blunt tips, but 

 those near the base of the rays are apt to be fusiform and subacute. 



The lateral or superomarginal row of spines is not very distinct; 

 its spines are subacute and much smaller than the actinals. They 

 form in some places two irregularly alternating rows, and differ but 

 little, in size or form, from the dorsal spines, though they may be 

 rather longer and more acute. 



The dorsal spines are small, either obtuse or acute, roughly 

 striated, very numerous, nearly uniformly scattered over the whole 

 surface, mostly standing singly, and do not form reticulations nor 

 any distinct median row. On the sides of the rays, in some places, 

 they form small transverse groups or combs on the connective 

 ossicles. About twenty to twenty-four can be counted in an irregular 

 series across the rays at the base, but they form no evident trans- 

 verse rows. 



The spines become rather larger, longer, and more crowded near 

 the ends of the rays, where they are surrounded by close wreaths of 

 minor pedicellariae. On the basal part of the rays and on the disk 

 the minor pedicellariae form small clusters around the bases of the 

 spines, and many other dermal ones are scattered between the spines. 



A few rather small, stout, subconical, dermal major pedicellariae 

 are scattered on the dorsal and lateral surfaces, and especially on the 



