STARFISHES OF THE PHILIPPINE SEAS. 431 



plate bears a spine ; beyond this about every fourth. Terminal plate 

 small, with a semicircular series of about 5 small spines on the distal 

 margin. 



There are no papulae between the marginal plates, nor actinally. 

 The larger papular areas (those on the median proximal region of 

 ray) contain 3 to 5 papulae ; the others 1 or 2. 



The body is overlaid by a tough skin of medium thickness which 

 covers everything but the sharp tips of the spines. It contains numer- 

 ous glands which are rendered visible by a short immersion in caus- 

 tic potash. The skin is crowded everywhere with minute perforated 

 plates sometimes as many as 4 deep but usually about 2 deep. They 

 are always so close that several overlap one another. They vary in 

 form from dumbbell-shaped rods with 1 or 2 perforations to round- 

 ish or oblong, elliptical, smooth plates with from 4 to 8 perforations, 

 the plates being predominant. The border of the plates is irregular, 

 with short protuberances. The medium-sized plates measure about 

 0.04 mm., and the largest 0.05 mm., longest diameter. 



Adambulacral plates with proximally 3 (distally 2 or 3) rather 

 slender spines in a vertical series, the 2 lower standing one above the 

 other on the furrow face of the plate, while the third is on the furrow 

 margin proper, and the series is united along the whole length of the 

 furrow by a continuous membrane, forming a serrated border to 

 furrow and usually closing it by interlocking more or less with the 

 spines of the opposite side. This spine is the longest of the 3, being 

 about one and one-half times the width of plate, acicular, sharp. 

 On account of the heavy membrane it appears stouter than it really 

 is. The spine below this is a trifle smaller, while the lowest is com- 

 pressed, curved at the base and shorter still. The three are united 

 by membrane, at least basally. Some of the proximal plates have 

 only 1 spine in the furrow, but usually there are 2. 



Mouth plates with 2 spines on the margin of furrow, and on the 

 furrow face of the plate 2 smaller spines, the upper usually but not 

 always larger than the corresponding (middle) adambulacral spine. 



Just back of the mouth plates and between them and the infero- 

 marginals (which extend proximad as far as the third adambulacral)" 

 is a fair-sized actinal intermediate plate bearing a spine similar to 

 those of the inferomarginals. On either side of this, and wedged 

 in between the third and fourth adambulacrals and first inferomar- 

 ginals, are 2 or 3 very small, almost rudimentary actinal intermediate 

 plates. These are, of course, invisible unless the integument is 

 thoroughly cleaned off. There are thus 5 or 6 actinal intermediate 

 plates entirely distinct from the rather numerous intermarginals 

 which form a large part of the actinal area of disk. 



Madreporic body small, raised, flat-topped, with few striations. 

 It is situated a trifle less than one-half r from center. 



