86 VERRILL 



lateral channels and among the ventral spines. Along the inner 

 edges of the adambulacral grooves, attached by pedicels, there are 

 many compressed and longer ones, some of which are larger than 

 the dorsals, others much smaller. These are mostly long-ovate, 

 often with incurved margins and blunt at the tips, which are den- 

 tate ; others are acute-lanceolate, and many are quite small. 



In the Museum of Yale University there are also several smaller 

 dry specimens of this species, agreeing very closely with the type. 



The best medium-sized specimens, with the radii 40 mm. and 

 180 mm., have the ratio as i : 4.5. The adambulacral spines are 

 slender, terete, subacute, arranged in one simple row. Those near 

 the mouth are not much lengthened; more distally many of them 

 are somewhat flattened, with obtuse or slightly spatulate tips. They 

 are mostly without minor pedicellarise, though small groups occur 

 on some of them. A few bear single, rather large, ovate-lanceolate 

 major pedicellariae, like the adambulacral pedicellariae. The latter 

 are rather numerous, attached to the inner edge of the adambulacral 

 plates, at or within the margin, by a long pedicel, which often bears 

 a cluster of minute acute pedicellarise at and below the base of the 

 large one ; the latter is unusually large, compressed-ovoid, subacute 

 or obtuse, with the tips of the jaws often denticulate. Their pedicels 

 are often as long as the adambulacral spines. The actinal spines 

 are large, subequal, and form four or five regular rows, proximally, 

 but usually only four beyond the middle of the ray; they become 

 much more slender distally ; those of the interbrachial region become 

 longer, fusiform, and often acute. Most of them are stout, clavate 

 or subcapitate, strongly sulcated on the outside and with the tip 

 finely striated all around. Most of them bear a small cluster of 

 minor pedicellariae on the outside. There are, apparently, only four 

 rows of peractinal and synactinal plates. The outer (peractinal) 

 ones often bear two spines. 



The marginal spines are larger and rather longer, similar to the 

 dorsal spines, and with subconic striated tips; they form a very 

 regular row, standing singly and well spaced on a row of somewhat 

 raised ossicles, and leave below them a wide and well defined mar- 

 ginal channel, which becomes dilated at the interbrachial region. 



The dorsal spines are similar in form but unequal in size, numer- 

 ous, arranged without any very evident order, but pretty evenly 

 spaced. They mostly stand singly on the nodes of the reticulating 

 ossicles, which form five to seven radial ranges and nine to ten in 

 transverse series. The dorsal spines bear a thin basal wreath of 



