114 BULLETIN 76, UNITED STATES NATIONAL MUSEUM 



and shallowly gouge-shaped (with rounded tip) as at stations 4431, 3110, 4552; 

 or rather slender, with a slight channel at the tip, as in the type. 



Straight pedicellariae (pi. 53, fig. Id) very scarce, practically absent on dorsal and 

 lateral surfaces. Small lanceolate pointed pedicellariae (0.5 to 0.6 mm. long in type) 

 occur in clusters on the actinal interradial area and scattered, proximally, on the 

 actinal surface of the ray. Small pedunculate ones are attached along furrow margin 

 and a few occur on the shortest mouth spine. 



Crossed pedicellariae 0.26 to 0.34 mm. long (pi. 52, figs. 3, 3a) occur in conspicuous 

 wreaths around the base of all the dorsal and superomarginal spines, and as a half 

 wreath, or cluster, attached to the base of the outer inferomarginal spine. There 

 are no pedicellariae on the inner inferomarginals nor on the actinals. The enlarged 

 subterminal lateral tooth of the outer side of jaw is rather better developed than 

 usual in this genus. A comparison with the figures of S. alexandri (fig. 2) shows a 

 number of differences. These are more marked in the fissiparous stages of the two 

 species than in the adults (figs. 2a, alexandri; 3c, 3d, Jieteropaes) . 



Papulae increase with age. In the type there are 8 longitudinal fairly regular 

 rows of papular areas. On each side of the carinal series: two rows of large area 

 with 6 or 8 papulae to an area; an intermarginal series with 5 or 6 papulae, and an 

 actinal with 3 or 4. 



Madreporic body just outside the pentagon of spines, medium-sized, flat, with 

 radiating striae. 



Color in alcohol. The type is faded yellowish, near a dull yellow ocher, with faint 

 cross-bands of faded brown. Other specimens, faded yellow with well-marked 

 cross-bands of brown; or sepia banded with faded yellow. The integument is marked 

 by fine channels, either darker or lighter than the surrounding integument. Actinal 

 surface yellowish. 



Variations. — The principal variations have already been mentioned in the forego- 

 ing description. The breadth of the ray at widest part varies from one-fifth to one- 

 sixth R. The rays are usually unequal however, and the longest is taken as a measure. 

 The most noticeable variations are the number of dorsolateral spines (these being 

 entirely absent, or in various numbers to a nearly complete series) and the number 

 of actinal spines. The suboral and adjacent adambulacral spines are also variable 

 in form, being sometimes markedly spatulate and gouge-shape, or slender lanceolate, 

 round tipped, and faintly gouge-shape. 



Straight pedicellariae are always few in number, lanceolate, never broadened, 

 toothed, or unguiculate. 



Anatomical notes (pi. 53, Jigs. 1, la-lc). — In the fully adult the skeleton consists 

 on the rays of 13 series of plates, namely, the carinals, and on either side, one series 

 of dorsolaterals, two of marginals, one actinal, one adambulacral, one ambulacral. 

 The carinals are four-lobed and closely imbricated. The dorsolaterals are unequal, 

 rather irregularly three or four lobed and joined to the carinal and supermarginal 

 plates by a slender ossicle which develops before the dorsolateral plates. In 

 young specimens the superomarginal and carinal plates are joined directly by 

 one or two of these slender ossicles which were not counted in the tally of plates. 



