SHALLOW- WATER STARFISHES 177 



ORTHASTERIAS MERRIAMI Verrill, sp. nov. 



Plate xviii, figures 4, 5 (type) ; plate xix, figures i, 2; plate lxxv, figures i-id 

 (spines and pedicellariae, No. 1181). 



A large six-rayed species, with long, round, gradually tapered 

 rays. Disk of moderate size. In the type-specimen, from off 

 Juneau, Alaska, the radii are 17 mm. and 112 mm.; ratio, about 



1:6.5. 



Dorsal ossicles broad, strong, convex, and firmly united, with 

 small papular spaces intervening; spines well spaced, conspicuous, 

 stout, but not very long, cylindrical or a little tapered, obtuse. They 

 stand singly on the ossicles and are surrounded at base by large 

 wreaths of pedicellariae. They form an irregular radial row and 

 two or three indistinct or imperfect rows each side of it, with 

 smaller spines interpolated. The upper and lower marginal spines 

 form equal regular rows, one spine on each plate. These spines are 

 larger and longer than the dorsals, mostly conical and subacute ; those 

 in the lower series are distinctly longer, especially near the base 

 of the rays. Those in the upper row bear large, dense, complete 

 wreaths of pedicellariae ; those in the lower row have them only on 

 the upper side. The two rows are separated by a naked channel 

 which becomes wide proximally and bears large, ovate major pedi- 

 cellariae, clusters of minor pedicellariae, and a row of papular pores. 

 At the base of the rays are two close rows of interactinal spines, 

 similar to the lower marginals. Of these, the outer row is close to 

 the marginal, but with small intervening papular pores, and it 

 extends nearly to the end of the ray. Its ossicles are rounded, con- 

 vex, and nearly as large as the marginals. The inner row extends 

 only about half the length of the ray. Many of the actinal spines 

 are flattened or acuminate at the tip ; others are obtuse. 



The adambulacral spines on the middle and distal plates stand one 

 or two to a plate, alternating irregularly, but on the proximal fourth 

 of the ray they are mostly one to a plate. They are rather stout, 

 shaped like the actinal spines, but smaller and shorter, varying in 

 size, mostly obtuse, but the smaller ones often acute. Toward the 

 mouth they become longer, more slender and subacute. The peroral 

 spines are large and strong and nearly meet over the mouth. The 

 two apical peroral spines, which are much stouter than the adorals, 

 but not so long, are straight, tapered, a little flattened, obtuse ; the 

 smaller side-spine is about half as long, but of the same shape. 

 They bear small, ovate, forficulate pedicellariae. The epiorals and 

 adorals are similar in form, distinctly longer than those farther out, 



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