ii8 DISCOVERY REPORTS 



Pseiidarchaster was known at this time. Hence it would seem fantastic even to consider 

 Astrogoniiim in connection with Pseiidarchaster. Perrier by the same logic transferred 

 Gray's Dorigona to Sladen's Nyrnphaster; yet no species oi Nymph aster was included in 

 Gray's genus, and none was known until many years after Dorigo?ia was described. 



Two species obviously related to discus are Ps. pectinifer Ludwig, Galapagos Islands, 

 812 fathoms, and Ps. dissonus Fisher, Bering Sea to Oregon, 859-1064 fathoms. Both 

 are large species, dissonus reaching R 170 mm. In dissonus the post-adambulacral 

 fascioles have become true valvate pedicellariae of a definite specialized form (Fisher, 

 191 1, p. 192, pi. 34, figs. 1-3 ; pi. 57, figs. 7, 7rt). In pectinifer these pedicellariae are as in 

 discus, but more developed on account of the larger size of the specimens. Ps. pectinifer 

 lives in a temperature of 38-5° while dissonus has a known range of 35-8 to 37'3° F., far 

 colder than the water at moderate depth in the Magellan region where typical discus is 

 found. 



Type locality. Challenger St. 307, Messier Channel, between the western coast of 

 Chile and Wellington Island, 140 fathoms, blue mud. 



Distribution. Magellanic and Falkland region, 140-283 m. 



Genus Ceramaster Verrill 



Ceramaster patagonicus (Sladen) 



Pentagonaster patagonicus Sladen, 1889, p. 269, pi. 46, figs. 3, 4; pi. 49, figs. 3, 4. 

 Ceramaster patagonicus Fisher, 1911, p. 214, pi. 37, fig. 4; pi. 38, figs, i, 2; pi. 60, fig. 3. — Koehler, 

 1923, p. 94. 



St. WS 76. 51° 01' S, 66° 31' 30" W, 110-113 mm., coarse dark sand, i specimen. 



St. WS 80. 50° 51' S, 63° 37' 30" W, 152-156 m., fine dark sand, 10 specimens. 



St. WS 225. 50° 20' S, 62° 30' W, 162 m., I specimen. 



St. WS 243. 51° 06' S, 64° 30' W, 144-141 m., coarse dark sand, 2 specimens. 



St. WS 801. 48° 26i' S, 61° 28' W, 165 m., I specimen. 



St. WS 804. 50° 22|' S, 62° 49' W, 150-143 m., I specimen. 



St. WS 805. 50° iQi' S, 63° 29' W, 148 m., I specimen. 



St. WS 813. 51° 35I' S, 67° 16I' W, 106-92 m., I specimen. 



St. WS 848. 50° 37I' S, 66° 24' W, 115-117 m., i specimen. 



St. WS 850. 51° i8f' S, 63° 30I' W, I specimen. 



This very widely distributed species has been figured and described by Sladen and the 

 writer. After examining the Discovery collection I am convinced that the specimens 

 from the north Pacific are patagonicus. Some of the small differences which I noted 

 between these specimens and Sladen's excellent figures disappear with a series of 

 southern specimens in hand. The latter are about as variable as the north Pacific 

 specimens. The largest example has R 63 mm., r 45 mm. 



It is possible that Perrier's Pentagonaster austrografiuhms (1891, p. 127, pi. 12, figs. 

 3 <7, 36) may prove to be a small patagonicus. All specimens of granularis attributed to 

 the north Pacific have turned out to be patagonicus. Perrier's 2 specimens came from 

 New Year Sound, 340 m., well within the range of patagonicus. 



