36 PROCEEDINGS OF THE NATIONAL MUSEXJM vol. 115 



of the Canadian Atlantic provinces and New England. Poranio- 

 morpha tumida appears not to have been recorded south of the 

 Labrador location given here. Others, like Pteraster pulvillus and 

 Henricia scabrior, are evidently rare south of Labrador. 



Comparison of this material with Pettibone's (1956) report on the 

 Blue Dolphin polychaetes from Labrador illustrates interesting dis- 

 tributional differences between the generally widely dispersed poly- 

 chaete species and the more restricted sea stars. Of 68 species of 

 polychaetes, only 9% (compared with 62% of the asteroids) are 

 Arctic-Subarctic and 37% (38% of the asteroids) are Arctic-to-Boreal ; 

 the remainder, including 25% with "cosmopolitan" distribution, 

 show no counterpart among the sea stars. 



I am grateful to Dr. F. M, Bayer of the United States National 

 Museum for making the Blue Dolphin collection available for study 

 and to Mr. D. C. Nutt for providing station data. 



Locations of all collection stations are shown in figure 1. The 

 Blu£ Dolphin station list is given in table 1. 



Ctenodiscus crispatus (Retzius) 



Asterias crispata Retzius, 1805, p. 17. 



Ctenodiscus crispatus (Retzius). — Fisher, 1911, p. 31, pis. 3 (figs. 1-4), 4 (figs 1-6). 



Collected at 9 stations; 27 to 174 m.; mud, silt, rock; 1949: BDI6 

 (47 specmiens), BD17 (1), BD19 (14), BD21 (4), BD27 (4), BD30 (1); 

 1950: BLD18 (10), BLD19 (23); 1951: BLDl, 11, 34 (13). 



All but 4 individuals have the usual 5 rays; 3 from BDI6 and 1 

 from BD21 have only 4. Two 5-rayed individuals show apparently 

 regenerating rays, 1 with a single new ray, the other with 2. Diameters 

 range from 6 to 78 mm., the majority being larger than 30 mm. 



These specimens were collected (fig. 1) between Hebron and St. 

 Lewis Inlet, and the species may be expected to occur along the full 

 length of the Labrador coast. It is limited here to cold water of high 

 salinity (fig. 2), to water of — 1° C. and less, and of a little less than 

 31%o to33°/oo. Typically a mud-bottom form, it occurred ahiiost 

 exclusively on mud in these collections. It is a circumpolar species, 

 ranging from Arctic to Boreal seas, 



Poraniomorpha tumida (Stuxberg) 



Solaster tumida Stuxberg, 1878, p. 31, pi. 6. 



Asterina tumida tuberculata Danielssen and Koren, 1884, p. 63, pis. 10 (figs. 5-7), 



15 (fig. 3). 

 Paraniomorpha tumida (Stuxberg). — Mortenson, 1910, pp. 257-258, pi. 16 (figs, 



6,7). 



Collected at 8 stations: 27-146 m.; mud, sand, rock; 1950: BLDl 

 (4 specimens), BLD2 (3), BLD5 (4), BLD7 (2), BLD8 (2); 1951: 

 BLD41 (2); 1952: I-2a, b (3), 1-17 (2). 



