28 HAWAIIAN AND OTHER PACIFIC ECHINI. 



pores evident. Genital pores large, close to madreporite in interradii. Unpaired 

 petal with about 56 pore-pairs on each side, 61 mm. long, 20 mm. wide at middle 

 and only 21 mm. half way between middle and tip; median area 10 mm. wide 

 with almost parallel sides; hence poriferous area rather more than five milli- 

 meters wide where widest; petal open by nearly 10 mm. Anterior petals 

 54 mm. long and 20 mm. wide, open by 5 or 6 mm. Posterior petals almost 

 exactly identical with anterior. Periproct submarginal, small, scarcely 4 mm. 

 across. 



Primary spines rough at tip; those of aboral surface quite small, seldom 

 exceeding 2 mm. in length; those of oral surface larger, near mouth about 4 mm. 

 long or if short, much stouter than those of aboral surface. Miliary spines 

 cylindrical or terete, quite numerous. Only ophicephalous and tridentate pedi- 

 cellariae were found. The former have heads about .30 mm. long and stalks 

 nearly twice as much; the valves (PL 123, figs. 13, 14) have the blades quite 

 spinous at base, with the opening low and broad and the margin finely serrulate. 

 The tridentate pedicellariae have the stalk about equal to the head; the valve- 

 are .15-.75 mm. long, narrow, straight, compressed and meeting for nearly half 

 their length. 



Color of holotype and other large specimens dull olive-green, brighter orally; 

 smaller specimens are more red-brown or red-purple and very small specimens 

 are quite distinctly reddish purple. In all the larger specimens, the ambulacra 

 on the oral surface are darker than the interambulacra but the boundaries 

 between the different areas are sharply zigzag lines, making rather of a hand- 

 some color-pattern, the distinctness of which varies greatly in the different 

 specimens. The color in life is not known. 



The holotype is from Albatross St. 2795, in the Gulf of Panama. 33 fins. 



There is a very good series of this interesting and well-characterized cly- 

 peastroid, taken by the Albatross at various points in the eastern tropical Pacific. 

 The smallest specimen is nearly circular in outline and only 6 mm. in diameter; 

 of course its identification is not certain but I see no reason for questioning it. 

 Others are 17, 26, 32, and 37 mm. in length, with the width practically the 

 same; in these specimens the form is more pentagonal. The largest specimen 

 is 196 mm. across but the length in the antero-postrrior axis is only 191 mm.: 

 the concavity of the posterior side is however 12 mm. The color of this speci- 

 men is, like that of the type, very distinctly olive-green, Inn there is good rw 

 for believing that this is due to the copper can in which they were stored for 

 many years; their labels are very green. The other specimens arc all mon 



