128 FISHER 



indistinguishable and spinelets very short granuliform, not ar- 

 ranged in evident pseudopaxillae as in levhiscula. Meshes 

 roundish quadrate, or irregularly polygonal, more open in some 

 examples than in others, containing sometimes i or 2 small 

 secondary ossicles with a few granuliform spinelets. Meshes 

 usually considerably wider than enclosing trabeculas, and with 

 5 to 12 papulae on proximal two-thirds of ray, 5 to 7 distally 

 (but fewer in small specimens). Spinelets not crowded, but 

 spaced, short, sharp, much slenderer, and fewer than in levius- 

 cula, often reduced to mere granuliform sharp elevations on 

 plate and more or less obscured by a tight thin skin ; arranged 

 along ridges irregularly, but in not over three rows, often in 

 only one irregular series. These rows are interrupted, dividing 

 the spinelets and granules into groups probably corresponding 

 to underlying plates, although no divisions are evident. There 

 are commonly 5 to 15 spinelets in one of these groups, but in 

 some specimens they are so obscured by the superficial mem- 

 branes that only the very tips of the spinelets are visible. They 

 are invisible to the naked eye, and are seen with difficulty under 

 a strong glass. Division into groups more evident on sides of 

 ray. 



Marginal plates regularly arranged. Superomarginal series 

 departing from interradial angle about midway between dorsal 

 center of disk and inner angle of jaw-plates ; occasionally rather 

 irregular near interbrachial angle ; plates sometimes transversely 

 elongated, with 10 to 12 spinelets. Inferomarginals slightly 

 larger or exactly equal to superomarginals ; 1 or 2 rows of in- 

 termarginal plates on basal fifth of ray ; also 1 or 2 rows of ac- 

 tinal intermediate plates, 2 extending about one fifth length of 

 ray, and 1 series for one half length, beyond which point in- 

 feromarginals and adambulacrals are in contact. Inter- and 

 inframarginal papula? ; 1 to 6 in an area. Marginal plates 

 also form fairly regular transverse series with adambulacrals, 

 although latter are more numerous than former. 



Adambulacral plates with 1 small spine deep in furrow ; on 

 some plates, especially in large specimens, a second may be 

 present just above it and in line. On actinal surface 2 larger 

 spines stand in an oblique transverse series on furrow margin 



