SHALLOW-WATER STARFISHES 11$ 



numerous as well as the dorsals. In two small specimens, with the 

 larger radii 24 mm. and 28 mm., the inferomarginal and the per- 

 actinal rows are single, but the superomarginal rows are double. 

 The spines in these are less clavate. The adambulacrals are irregu- 

 larly diplacanthid ; distally they are slender and subclavate, obtuse ; 

 proximally they become much more slender, longer, tapered, sub- 

 acute. They have large clusters of minor pedicellariae, with some 

 small major pedicellariae intermixed. Small clusters of minor pedi- 

 cellariae are also found on the lateral and dorsal spines. Dermal 

 major pedicellariae of small and moderate sizes are numerous between 

 the lateral rows of spines. They are ovate and ovate-lanceolate in 

 form, and subacute; others, much smaller and mostly ovate, are 

 found with them and also on the dorsal surface. The papular areas 

 are small. Color in life : " Above, deep olive green with the tips of 

 the spines whitish; those of the edges very pink" (Stejneger). 

 The type (No. 15841, U. S. Nat. Mus.) was taken February 2, 

 1883, at Bering Island, Commander Is., by Dr. L. Stejneger. Three 

 smaller specimens are from Petropaulski, Siberia, Afbatross col- 

 lection. 



This species is evidently related to A. acervata borealis. V It differs 

 mainly in the pretty regular arrangement of the dorsal spines in three 

 or five multiple rows ; in having the superomarginal rows of plates 

 double- or triple-spined, and the inferomarginals and peractinals 

 double-spined when adult. These features I have not seen in the 

 Atlantic borealis, nor in the Pacific form, A. acervata. The young 

 specimens resemble some species of Leptasterias, like L. dispar. 



The species very imperfectly described by Brandt, from Siberia, 

 has always been doubtful, Ludwig considered it the same as 

 A. acervata Stimpson (see p. no), but that does not seem very prob- 

 able. It is more likely to have been this species, if either. 



Brandt's original description was based on a colored drawing of 

 a very young specimen (" diameter of disk, one inch; length of rays, 

 one to one and one-fourth inches "). 



Aside from the size and color, the only other characters given are 

 that the dorsal spines ("papillae") are numerous and "truncate- 

 capitate," reticulate, and form " subangular" series " on the rays. 

 The last statements do not apply very well to A. acervata, but would 

 apply very well to this species, and also to some of the six-rayed 

 varieties of epichlora. But the latter is not known to me from the 

 Arctic Ocean nor from Siberia, 



The capitate form of the larger spines is characteristic of all these 

 forms, as well as many others. 



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