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, Pterasterids ; in Joum. 

 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, ofT St. George Island, in 30 meters (Ludwig) . 



Genus Diplopteraster Verrill. 



Diphptcraster Verrill, Amcr. Joiirn. Sci.. xx. p. 400, 1880. Fisher, op. cit.. 

 191 ift, 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, cis 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. vm, figs. 1-17, 1877. 

 Retaster T 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., 189s, p. 202. Fisher, op. cit., igitb, p. 371, pL cvn, figs., 1, 2. 



