ECHINODERMS OF CHALLENGER BANK, BERMUDA. 357 



nected together by a thin membrane without granules on either sur- 

 face. Subambulacral spines conspicuous, stout, shghtly flattened, 

 with blunt tips, about 2 mm. long and not quite a millimeter thick; 

 there are half a dozen subambulacral spines on the first half dozen 

 adambulacral plates, but further out there is only one such spine to 

 each pair of adambulacral plates, or occasionally the ratio is one to 

 three. Oral plates concealed; oral angles with half a dozen marginal 

 spines on each side, and several pedicellariae and two stout suboral 

 spines (one on each plate) on the surface. Color light yellowish- 

 brown without any markings. The specimen is now without any 

 trace of the color the sea-star had in life. 



Holotype, M. C. Z. No. 2758. Bermuda: Challenger Bank, 303^ 

 fms. Aug. 1, 1903. 



This is one of the most clearly marked members of the genus, not 

 at all like the other West Indian species. The small skeletal plates 

 and unusually large papular areas give it a characteristic facies, while 

 the size, form and arrangement of the pedicellariae are also very dis- 

 tinctive. As no species of Ophidiaster has been found north of south- 

 ern Florida, not even in the Bahamas, the occurrence of this fine new 

 form on the Challenger Bank is of exceptional interest. 



Stephanasterias gracilis. 



Asterias gracilis Perrier, 1881. Bull. M. C. Z., 9, p. 4. 



Stephanasterias gracilis Verrill, 1899. Trans. Conn. Acad., 10, p. 223; 1915, 

 Bull. Univ. Iowa: Nat. Hist., 7, p. 25; pi. IX, figs. 2-2e. 



This is a very small sea-star, the largest specimen of the more than 

 sixty in the M. C. Z. having R only 20 mm. and the great majority 

 of the specimens are much smaller than that. It has been recorded 

 from numerous stations in the AVest Indian region in from 56 to 

 270 fms., but it has never been reported from so far north as the 

 Bermudas nor from such shallow water as that which covers the 

 Challenger Bank. There are four specimens, however, in the collec- 

 tion made by the party of 1903, and the depth at which they were 

 taken is recorded as 30}^ fms. They are all very small and as usual 

 in the species, they show great diversity in form. The largest has 

 three arms with R = 9 mm. while the three on the other half of the 

 body has R = 5-6 mm. A second specimen has the arms 9, 8, 7, 5, 4 

 and 4 mm. long, the three longest opposite the three shortest. A third 

 specimen has three arms about 7 mm. long and on the other side, 

 three about Ij^ mm. The smallest specimen has but three arms, 



