47:2 SALMACIS BICOLOR. 



genital plates of uniform size ; madreporic genital but slightly larger. Anal 

 system covered by comparatively few large polygonal plates carrying small 

 tubercles, irregularly arranged, with smaller ones between them. The ocu- 

 lar plates are irregularly pentagonal, small, excluded from the anal system; 

 the genital plates carry a ring of secondary tubercles near the anal system. 

 Interambulacral space covered by tubercles very uniform in size, arranged 

 in vertical and horizontal rows decreasing gradually from the ambitus to the 

 abactinal pole ; the vertical rows adjacent to the poriferous zone are slightly 

 larger than the others, as many as twelve vertical rows of ambitus at speci- 

 men measuring 50" 1 " 1 ' in diameter. The coronal plates are narrow; the plates 

 cany in addition to the primary spines an irregular horizontal row of small 

 granules above the primary tubercles. In the ambulacra! space the two 

 primary vertical rows adjacent to the poriferous zone are as large as the 

 interambulacral primaries; the median space is Idled with from four to five 

 irregular vertical rows of somewhat smaller tubercles. In large specimens 

 the second inner vertical rows an- frequently as large and regular as the 

 outer row. On the ambulacra! plates a few granules occupy the upper part 

 of the coronal plate. On the actinal side of the test we find that at the 

 ambitus and below it the tubercles rapidly increase in size, and cover the 

 whole actinal surface close to the actinostome with tubercles of very uniform 

 size arranged in regular horizontal rows, hut becoming slightly smaller 

 towards the actinostome. The median ainludacral tubercles, however, dimin- 

 ish gradually in size towards the actinostome. The poriferous zone is broad; 

 pores large, regularly arranged in arcs of three pairs. The spines of the test 

 above the ambitus are short, pointed, slender, of a greenish color, banded 

 with five or six transverse hands of violet. The spines of the actinal surface 

 are much longer and broader, frequently flattened, gradually tapering and 

 blunt at the extremity, and similarly banded to the spines above the ambitus. 

 The color of the test, when dry, is yello wish-brown. The pores at the median 

 junction are small, and the horizontal sutures of the coronal plates slightly 

 furrowed. 



Red Sea ; [ndial] Ocean ; Mozambique. 



