NO. 4 ziesenhenne: new eastern pacific sea stars 203 



They are stouter and somewhat longer than the corresponding supero- 

 marginal spines. There are fewer secondary spines and spinules compared 

 with the superomarginals. The terminal plate is small, wider than long, 

 densely covered with spinules. 



Adambulacral plates more than twice as wide as long, widely sepa- 

 rated by deep, broad, naked grooves. The center of the plate is raised in a 

 prominent, transverse ridge bearing 3 or 4 subequal, stout, tapering spines, 

 the longest more than the combined length of two adambulacral plates. 

 The outermost spine slightly the longest. In addition, there may be from 

 3 to 9 sharply tapering spinelets on the outer edge of ridge. Furrow mar- 

 gin ridge prominent, bearing 2 to 4 subequal, heavy, blunt, slightly 

 curved, capitate furrow spines, the outer two shortest, middle one or pair 

 equal to the length of one adambulacral plate. Tube feet in 2 rows ; suck- 

 ing disks well developed, ampullae double. 



Mouth plates oval shaped, more than twice as long as wide; actino- 

 stomial margin widest, broadly rounded; distal margin narrow, convex; 

 actinal surface highly convex. Marginal spines, 5 or 6, broad and flat- 

 tened, tapering and bluntly tipped. Innermost spine longest, about two 

 thirds the length of oral plate, next shorter, and the remaining diminish- 

 ing rapidly in size to the short, delicate outer spine. On the actinal sur- 

 face are 3 to 5 large, stout, tapering, blunt spines, half the length of oral 

 plate and 2 to 4 smaller secondary spines. Distally on each plate is a 

 longitudinal row of 3 to 8 short, sharp spinules. Actinal intermediate 

 plates 4 to 8, confined to the disk, oval shaped, wider than long, each bear- 

 ing 3 to 5 transverse rows of 3 to 4 short, sharp, granulelike spinules. 



Papulae very numerous, absent in a narrow interradial line of the 

 disk and the distal two thirds of the ray. They are present on the disk and 

 basal portion of ray, where there is some semblance of 4 longitudinal rows, 

 each with an irregular transverse series of 3 to 6 papulae. Longitudinal 

 rows are separated by 3 longitudinal rows of loosely compacted, large 

 paxillar plates ; the two central rows consist of 2 or 3 transverse papulae, 

 extending to the third or fourth superomarginal. Outer rows consist of 

 3 to 5 transverse papulae, extending to sixth, seventh, or eighth supero- 

 marginal ; and in larger specimens there is a continuation of a single row 

 of papulae, close to the superomarginals extending to the thirteenth su- 

 peromarginal. In a specimen of R=90 mm. each papular area contained 

 about 260 papulae. The youngest specimen of R=32 mm. contained 62 

 papulae in each papular area. 



