30 HAWAIIAN AND OTHER PACIFIC ECHINI. 



Clypeaster rarispinus. 



De Meijere, 1903. Tijdsch. Nederland. Dierk. Ver., ser. 2, 8. p. 7. 



The only addition I have to make to de Meijere's account is the presence of 

 ophicephalous pedicellariae, which he did not find. They are small (heads only 

 .15-. 20 mm. long) and not at all common. The triphylfous pedicellariae have 

 valves only .07 mm. long, but the stalk is seven times as long as the head. In 

 the tridentate the valves are curved, .43 mm. long and have the blade gradually 

 widened near tip. They are thus somewhat like those of audouini, and the mili- 

 ary spines are much like those of that species. The Siboga took rarispinus at 

 four stations in the Dutch East Indies and it is not yet known from elsewhere. 



Clypeaster ochrus, 1 sp. now 

 Plate 141, figs. 1-3. 



Length, 94 mm.; breadth, 83 mm.; height, 24 mm.; mouth sunken 12 mm. 

 below sides of test. Test moderately high and rather evenly arched, deeply 

 concave beneath; margins 8-9 mm. thick or rather more than .08 of test length. 

 Tuberculation of test, rather coarse; primary tubercles small, with sunken 

 areolae, about 100 per sq. cm. of test surface, aborally; ridges between pore-pairs 

 of unpaired petal with a single series of four to six primaries; miliary tubercles 

 very numerous, probably twenty times as many as primaries, covering the 

 quite uniformly. Madreporite pentagonal, 4 mm. across: ocular plates and 

 pores not very distinct. Genital pores large, close to interradial angles of madre- 

 porite. Unpaired petal with about fifty-three pore-pairs on each side 32 mm. 

 long, 15 mm. wide at middle, and 16.5 mm. wide half way between middle 

 and tip; median area, 9 mm. and 10 mm. at the same two points respect i\ 

 hence poriferous areas about 3 mm. across where widest; petal open by fully 

 5 mm. Anterior petals somewhat shorter and wider, about 30 by 18 mm., 

 not quite so open at tip. Posterior petals as long as unpaired ami as broad as 

 anterior; open by about 4 mm. Periproct 3 mm. from margin about 5 mm. 

 across, covered with numerous small, miliary bearing plates. 



Primary spines of aboral surface, rather slender, perfectly smooth, about 

 _' mm. long; on oral surface, primaries longer especially about mouth where 

 they are 4 mm. long. Miliary spines cylindrical or terete, not peculiar but 



1 dixpfa = pale, sallow, in allusion to its light yellow-brown color. 



