188 HAWAIIAN AND OTHER PACIFIC ECHINI. 



fasciole is very distinct and is widest at the ends of the petals. Petal III is 

 about 14 mm. long and 4-5 mm. wide, and is rather markedly depressed. The 

 interambulacra between it and the adjoining petals are so compressed as to be 

 distinctly carinate. Petals II and IV are very little sunken, widely diverging 

 and distinctly curved, and measure 11 mm. long by 3.5 mm. wide. They have 

 about twenty-one pore-pairs on each side. Petals I and V are 5.5 mm. long 

 by less than 3 mm. wide, moderately diverging and little depressed. They 

 have about twelve pore-pairs on each side. There are two large genital pores; 

 their relative position and the arrangement of the plates of the abactinal system 

 will be easily understood from the figure (PI. 148, fig. 1). The periproct is 

 situated high upon the posterior, truncate end of the test; it is 5 mm. high, 

 but scarcely 3 mm. wide. Some 12 mm. below it is a narrow fragment of an 

 anal fasciole, irregularly V-shaped and not more than 10 mm. long altogether. 

 At each of the lower posterior corners of the test are four somewhat enlarged 

 tube-feet but they are not conspicuous. Below the periproct is an area about 

 10 mm. high and 3 mm. wide at the top which is bare of primary and secondary 

 tubercles; near the lower end it becomes pointed by the encroachment of second- 

 ary tubercles. The sternum is about 16 mm. long by 15 mm. wide posteriorly; 

 it is thickly covered with primary tubercles. The labrum is about 4 mm. long 

 and carries only three primary tubercles. The peristome (PI. 148, fig. & is 

 pentagonal, much wider than long, and covered by but few plates; it is not at 

 all sunken and even the labrum projects little. The color of the test in the 

 dry specimen is very pale brown; the spines are nearly or quite white. 



The primary spines are slender and very fragile. On the upper surface 

 and sides of the test they are only about 2 mm. long, but along the petals they 

 become 3 or 4 mm. long and anteriorly, near the oral surface they are 5 mm. 

 On the sternum they are 4 or 5 mm. long and conspicuously spatulate at tip. 

 Pedicellariae are numerous and of two different kinds. The globifenms arc 

 fairly common and are like those of Hemiaster expcrgitus as figured by Morten- 

 sen (1907. Ingolf Ech., pt. 2, pi. 15, fig. 24), but the valves have a relatively 

 higher and narrower base; they are .45-. 60 mm. long and the base is about .30 

 mm. high and equally wide. The rostrate are abundant and remarkable for 

 the greatly curved valves; these (PI. 146, fig. 10) are .25-.65 mm. long measured 

 on the chord but, .30-.85 measured on the are. The trident at e are equally 

 remarkable, but are very rare; the valves (PI. 146, fig. 9) are about .70 mm. 

 long and have conspicuous sharp teetli on the hack, as well as on the margins, 

 Ophicephalous and triphyllous pedicellariae are very infrequent or at least hard 



