I/O VERRILL 



longer and more slender. Four contingent pairs of plates, besides 

 the two apical ones, form the compressed oral carinae, each bearing 

 a single spine. The epioral spines are like the others. The perorals 

 consist of an apical pair of shorter and stouter spines and a divergent 

 auxiliary spine, of about half their length, on each side. 



Major pedicellariae of different sizes and forms are scattered over 

 the dorsal surface as well as on the lateral channels and on the mar- 

 gins of the ambulacral grooves; others occur on the actinal areas, 

 on the tips of the jaws, and on the adambulacral spines. The largest 

 occur on the marginal plates. These are compressed, long-ovate, 

 oblong-ovate or oblong-lanceolate in a front view; some are very 

 stout, with somewhat spatulate rounded tips, in a profile view ; a few 

 are denticulate, others acute. Those of the ambulacral region are 

 more compressed and usually much smaller, though the larger ones 

 are here as wide as the adambulacral spines ; most of these are long- 

 ovate or lanceolate and acute. Those on the back are mostly acute- 

 ovate. 



The minor pedicellariae are rather unusually large and form dense 

 clusters around all the dorsal and upper marginal spines at about 

 mid-height, while smaller groups occur on the actinal and adambu- 

 lacral spines. Papulae are small and numerous. The ambulacral 

 grooves are wide; the pores, which form four regular rows, are 

 narrow-elliptical, with flaring lips. 



A smaller specimen from Queen Charlotte Islands (Canadian Geo- 

 logical Survey, 1878) has the radii 12 mm. and 72 mm.; ratio, 

 i : 6. The dorsal spines are more numerous and longer than in the 

 type, and stand in about five rows. They are all nearly equal and 

 rather isolated, except those in the median radial row, where they 

 stand in a pretty close line. They all bear a dense wreath of minor 

 pedicellariae on a sheath, at about mid-height. The dorsal ossicles 

 are strong and closely united, convex, with a mammilliform elevation 

 and a central pit, where the spine was attached. 



The upper and lower marginal spines are a little longer, but similar 

 to the dorsals; both are in regular rows, but the lower ones often 

 stand two on a plate proximally. Actinal spines similar, in one row. 

 Adambulacral spines long and slender, but rather shorter than the 

 actinals, except on the adoral and epioral plates, where they become 

 decidedly longer. They stand irregularly, one and two to a plate. 

 Adoral carinae compressed, formed by two or three contingent plates, 

 besides the epiorals. Peroral spines of moderate length. 



