SHALLOW-WATER STARFISHES lOQ 



in A. polaris, and of greater diversity in size, the larger ones being 

 collected in heaps which form three regular longitudinal rows on the 

 rays. These large spines are capitate, with obtusely conical and 

 striated heads; there are usually about six spines in each heap, the 

 central one being much the largest and overtopping the others, which 

 form a circle around it. The small spines between the heaps are 

 quite uniform in size, and have globular tips. Disc surrounded by a 

 ring of six heaps of spines, within which there is sometimes another 

 ring of the same number, and always a heap in the middle. Madre- 

 poric plate surrounded with a circular canal and a ring of thirteen 

 spines. All the spines, both ventrals and dorsals, are surrounded by 

 minor pedicellariae, as m A. polaris. The major pedicellariae, which 

 are most numerous on the sides of the rays, are scattered, and very 

 irregular in size, varying from one two-hundredth to one-twentieth 

 of an inch in length ; the largest ones are stout, as long as broad, 

 conical, or almost globular, having valves with broad, dentated 

 extremities. Papulae numerous, scattered, and often forming groups. 

 Color, in life : above, clouded with very dark brown ; madreporic plate 

 cream-colored. Sides of rays, and inferior surface, of a yellowish 

 cream-color. Diameter, five and a half inches. 



" Habitat, Behring's Straits, on clean gravelly bottoms, in from 

 five to fifteen fathoms. U. S. North Pacific Expedition. Wm. 

 Stimpson." 



Dr. Stimpson was the naturalist of the North Pacific Exploring 

 Expedition, under Ringold and Rogers, and therefore probably made 

 his notes on the colors from personal observation of living specimens. 

 I have received from the U. S. National Museum a specimen from 

 Cape Smith, Alaska (No. 7630), which agrees very closely with 

 Stimpson's type. The radii are 15 mm. and 55 mm. The dorsal 

 spines are formed as described by Stimpson and are conspicuously 

 acervate ; but though the clusters are somewhat in three radial rows 

 on the rays, the rows are decidedly irregular. Between the clusters 

 the ossicles are obviously areolate or reticulate, and bear small capi- 

 tate spines. The upper marginal spines are about equal in thickness 

 to the larger dorsals and rather longer ; they stand either one or two 

 on a plate. The lower marginals are longer but not so stout, and 

 form a regular row, one to a plate. There is a short intermarginal 

 row of smaller spines proximally. The peractinals are similar to the 

 lower marginals and form a regular, simple row close to the latter. 

 Subactinal row short. The adambulacral spines are irregularly 

 diplacanthid ; they are moderately long, scarcely tapered, obtuse. 



