SHALLOW- WATER STARFISHES 2/9 



present unique example, of which unfortunately no previous original 

 account exists, may be distinguished in a conspicuous manner by the 

 absence of the so-called oscular orifice of Sladen, in the supradorsal 

 membrane (comp. because of this and some others among the fol- 

 lowing required characters : Sladen, Asteroidea of the ' Challenger ' 

 Expedition, Preliminary Notice, Part I, Pterasteridae ; in Journ. 

 Linn. Soc., London, xvi, p. 191, 1882). If all other characters did 

 not correspond with those of the genus Pteraster, one would be war- 

 ranted in founding a new genus on the above-mentioned absence of 

 the so-called oscular orifice. As I propose to give in another place a 

 more detailed discussion of the organization of this new species, and 

 a description of the numerous quantity of young forms found in the 

 nidamental cavity, I shall content myself for the present with a short 

 account, setting forth the evident differences between this and other 

 known species." (Ludwig.) 



Bering Sea, off St. George Island, in 30 meters (Ludwig). 



Genus Diplopteraster Verrill. 



Diplopteraster VERRILL, Amer. Journ. Sci., xx, p. 400, 1880. Fisher, op. cit., 

 191 1&, p. 370. 



Thick, pentagonal, or short-rayed, with a thick outer integument 

 containing strong reticulated muscle bands. Marginal membranous 

 fold wide and thick. Oral spines webbed together. Tube-feet in 

 four rows. Fans of adambulacral spines and furrow-series alter- 

 nately larger and smaller, and alternately placed farther forward 

 and back. 



In life, the surface secretes a large amount of mucus, when taken 

 from the sea, and emits strong phosphorescent light. 



When fresh the surface appears smooth or nearly so. In pre- 

 served and contracted specimens the larger paxillary spines push up 

 against or through the dorsal membrane, so as to give it a more or 

 less bristling or spinose appearance, as happens in most other 

 species of Pterasteridae. 



DIPLOPTERASTER MULTIPES (Sars) Verrill. 



Pteraster multipes M. SARS, Vidensk. Selskabs. Forhandl., 1865, p. 200; Fauna 



Litt. Norvegiae, p. 65, pi. vni, figs. 1-17, 1877. 

 Retaster ? multipes SLADEN, op. cit., pp. 477, 478, 800, 1889. 

 Diplopteraster mulitpes VERRILL, Amer. Journ. Sci., xx, p. 400, 1880; Ann. 



Report U. S. Fish Comm., for 1882, x, p. 659, 1884; op. cit, xi, Expl. 



by the Albatross in 1883, p. 542, pi. 14, fig. 43, 1885; Distrib. Echinod., 



op. cit., 1895, p. 202. Fisher, op. cit., 191 ib, p. 371, pi. cvii, figs., i, 2. 



