318 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.8 



Dendraster rugosus^^, new species 

 Plate 52, Figs. 40-41 



Length 49 mm, breadth 47 mm, height 9 mm; the breadth is thus 

 ver>' nearly equal to the length and it is probable that in fully grown indi- 

 viduals the equality is complete. Lower surface almost completely flat, the 

 oral area being very slightly depressed (when the animal is upside down). 

 Test rather evenly elevated from margin to apex, which is definitely 

 posterior in position, less than 20 mm from posterior margin. Petaloid 

 area 26 by 30 mm with the anterior petal the longest and narrowest. 

 Tuberculation of test very close and fine abactinally but with numerous 

 primary tubercles scattered irregularly about, mostly in the petals or near 

 the test margin; tuberculation of oral surface rather sparse except near 

 margin. Posterior petals about 11 mm long and 5.5 mm wide; they are 

 quite straight and diverge markedly, the inner margins being 12 mm apart 

 at tips ; poriferous areas very narrow, about a millimeter wide, and the 

 ridges between pore-pairs are so narrow they carry no primary tubercles. 

 The areas between the poriferous zones carry longitudinal series of rela- 

 tively large tubercles, about 4 basally but only 2 or 1 near the tips ; these 

 series are more or less irregular and incomplete but give a definite char- 

 acter to the petals. Anterior lateral petals essentially similar but larger, 

 14 by 6.5 mm; the poriferous zones are wider than in the posterior pair 

 but are still quite narrow. The anterior unpaired petal is about 16 mm 

 long but only 5 mm wide, for the poriferous zones are only a little curved 

 and are as narrow as possible. Interporiferous areas in all 3 anterior petals 

 show their primary tubercles rather conspicuously in 4 somewhat imperfect 

 but still evident longitudinal series. Whole abactinal surface closely cov- 

 ered with spines; the primary spines, borne by the large tubercles of the 

 petals and by similar tubercles scattered over the interambulacral areas, 

 are about 2 mm long, nearly white and rather sharp, the other spines are 

 scarcely half as long and are thickened at the tip and rather bluntly pointed. 

 Genital pores 4, fairly large ; the 5 ocular pores much less distinct. Mouth 

 small, largely concealed by the long (4 or 5 mm) white spines crowding 

 around it. Anterior primary spines of oral surface, 2 or 3 mm long, curve 

 outwards to left and right on the anterior fifth of the test. Pedicellariae 

 very small and hard to detect, not distinctive. Color of bare test pale ecru 

 drab or pale vinaceous drab, spines whitish. 



"^^ rugosus — rough, in reference to the appearance caused by the numerous 

 projecting primary spines. 



