HYDROCORALS OF THE NORTH PACIFIC — FISHER 495 



But the other Stylasters and Alloporas appear to have no close 

 counterparts in the Athmtic with the exception of a race of the widely- 

 distributed Stylaster eximius reported by Dr. Broch from the Okhotsk 

 Sea. It is certainly premature to speculate on the distribution of the 

 species found in the Okhotsk Sea, a region that has hardly been 

 scratched by the dredge. Allopora boreopacifica is common to the Sea 

 of Japan and the Okhotsk Sea. Allopora scabiosa has a closely related 

 form in Sagami Bay (Hattori collection), but Allopora solida is not 

 very closely related to any known species. It v/ill hardly be sur- 

 prising if A. sfejnegeri and A. brochi are eventually added to the 

 Okhotsk fauna. 



So far as the western coast of the United States is concerned only 

 five species are present: Allopora californica, A. venusta, A. verrUli, 

 A. porphyra, Errinopora pourtalesii. No true Stylaster has yet been 

 found. 



I have also examined material from the region of the Galapagos 

 Islands, which is well represented in the National Museum. This 

 fauna has nothing to do with that of the north Pacific. If it points 

 anywhere it is to the West Indian region. Cryptohelia is the domi- 

 nant genus. 



As a parenthetic observation on the distribution of the Stylasterina, 

 the only species known to inhabit the Hawaiian plateau is Stylaster 

 sanguineus. Probably Distichopora violacea also occurs, although I 

 can find no record. These are shallow-water tropical forms. Although 

 I was in constant and close touch with all the detailed and carefully 

 planned deep-water dredging done by the Albatross in 1902, I do not 

 recall a single specimen of deep-water Stylaster, such as occurs in the 

 East Indies, or of any other hydrocoral for that matter. The great 

 depths surrounding the Hawaiian group appear to constitute an 

 effective barrier, although the planulae of Stylaster sanguineus are 

 probably transported in warm surface currents. If the last observa- 

 tion is not true, the only alternative is to conclude that Stylaster 

 sanguineus reached the Hawaiian group when those islands were part 

 of a land mass extensive enough to afford a shallow-water path from 

 some Indo-Polynesian center of dispersal. If such were the case it 

 seems likely that species characteristic of depths of from 100 to 800 

 fathoms, such as Cryptohelia, would also have traveled along a "lower 

 road." 



In table 1 are listed all the Albatross dredging stations in the north 

 Pacific at which the species described in this report were taken, with 

 all pertinent data for each station, and species taken at each station. 



The Stylasterina naturally occur on a bottom that provides some 

 solid objects permanent enough to afford attachment for the colony. 

 Yet the nature of this is not always apparent from the data recorded, 

 as for instance station 2852, "black sand" {Allopora campyleca) ; sta- 



