SHALLOW-WATER STARFISHES IO3 



or five regular rows ; the upper marginals are a little more removed, 

 but the others are closely united in a tesselated manner, leaving only 

 small papular pores between them. The exposed part is convex, 

 with facets and pits for the spines. They are slightly four-lobed, 

 but are so imbricated that they appear squarish with rounded 

 corners, or ovate-triangular. 



The dorsal spines consist of two very unequal kinds. The larger 

 ones are few in number and are widely scattered, except in the 

 median radial line, where they form a pretty regular row ; the others 

 stand somewhat in quincunx, but may belong to about three imper- 

 fect rows on each side. These spines stand on the larger plates at 

 the intersections of the reticulations. They are rather large, short, 

 and thick, not much higher than broad, with enlarged, truncate or 

 capitate tips, striated on the sides and rough on the top. They are 

 about 1.5 mm. broad. Between these there are many very small 

 inconspicuous spines, arranged mostly in single rows along the 

 narrow ossicles that form the sides of the reticulations. Some of 

 them are acute, but most are slightly clavate with rough or spinulose 

 tips. Both kinds are scattered irregularly on the central area of the 

 disk. 



Small minor pedicellariae are thickly scattered over the whole 

 surface between the spines and on the papular areas, and also form 

 wreaths around the larger spines. 



The superomarginal spines form simple regular rows, and are 

 much like the large dorsals in length and form, but are smaller. The 

 intermarginal channel is well defined and of moderate width. The 

 inferomarginal spines form a regular row, mostly simple, but fre- 

 quently stand two on a plate distally. They are followed, proxi- 

 mally, by two pretty regular close parallel rows of actinal spines, of 

 about the same size and shape. These three rows of ventral spines 

 are longer than the superomarginals and less clavate, but about as 

 stout. They are blunt and sulcate at the tips. The first subactinal 

 row extends only to about the end of the proximal third of the ray ; 

 on the proximal fourth there is also a simple, short row of synactinal 

 spines. 



The synactinal ossicles are small, with an oblong or elliptical 

 surface, and mostly bear a single spine ; they extend only to about 

 the proximal third of the rays. 



The adambulacral spines stand two on a plate, or else in certain 

 parts one and two alternately, thus forming two or three crowded 

 rows. They are unequal, not very slender, the inner ones slightly 

 tapered, the outer ones stouter, blunt, as long as the ventral spines, 



