NORTH PACIFIC OPHIURANS IN NATIONAT. MUSEUM — CLARK. 



83 



tion on face of each jaw. Oral papillae about five on a side, those at 

 tip of jaw rather large and pointed. Genital slits inconspicuous but 

 genital scales large and very conspicuous from above; each scale 

 carries a closely crowded series of about thirty marginal papillae 

 which are flat and truncate orally but become very slender and some- 

 what pointed at upper end of scale. Basal under arm plates wider 

 than long and wider without than within, each with a conspicuous 

 swelling or keel occupying median part of plate; succeeding plates 

 squarish or hexagonal without a keel, gradually becoming longer 

 than wide. Side arm plates high but narrow, and not meeting above 

 or below until far out on terminal part of arm; each plate carries two 

 or three true arm spines and a marginal fringe of secondary spines; 

 secondary fringe resembles arm comb, consisting at lower end of 

 flat, truncate papillae and above of slender, more spine-like processes; 

 altogether there ma}^ be a dozen or more teeth in this fringe; lowest 

 true arm spine just above outermost tentacle scale, for which it might 



Fig. 25.— Ophiura stiphra. X3. a, from above; 6, from below; c', side view of base of arm. 



easily be mistaken as it exceeds it very little in size; second arm spine 

 a little longer and usually quite pointed; it is nearly its own length 

 above lowest; third spine, when present, is at extreme upper corner 

 of side arm plate and is smallest of three. Oral tentacle pores large, 

 not opening into mouth slit, protected by about five large flat scales 

 on each side; basal tentacle pores of arm similar but with as many 

 as eight scales on proximal side and only three or four on distal; 

 beyond about eighth or ninth pore there are no scales on distal mar- 

 gin of pore but there are three or four on the proximal side far out on 

 arm; outermost tentacle scale quite similar in form to lowest true 

 arm spine. Color (dried from alcohol), fawn color, pale buff, pale 

 gray, or whitish. 



Localities.— Albatross station 3700, off Honshu Island, Japan, 63 

 fathoms, volcanic mud, sand, 1 specimen; station 3708, off Honshu 

 Island, Japan, 60 to 70 fathoms, green mud, volcanic sand, ashes, 

 3 specimens; station 3713, off Honshu Island, Japan, 45 to 48 



