HYDKOCORALS OF THE NORTH PACIFIC FISHER 501 



The ampullae are characteristic. The probable male ampullae are 

 about 0.75 mm in diameter, about the same height, aud the base is 

 sometimes slightly constricted. The surface is very uneven (pi. 54, 

 fig. 2; pi. 47; pi. 48, fig. 2). The probable female ampullae (pi. 47, 

 fig. 3; pi. 48, fig. 1) are 1 mm in diameter. The surface is uneven, 

 subrugose but less so than in the male, and there are no irregular 

 protuberances such as usually characterize the male ampullae. 



Coenosteum is of coarse texture. Surface of male fragments (e. g., 

 pi. 48, fig. 2) is covered with imequal, compound, thorny outgrowths 

 of very many different forms and sizes. These may form narrow, 

 mostly longitudinal ridges on the face of colony, and also decurrent 

 from the rim of cyclosystems. The surface of the female colony 

 (pi. 47, fig. 3) is smoother, but on the peripheral branchlets are 

 conspicuous smooth spiny outgrowths, sometimes extensions of septa 

 of cyclosystems, sometimes independent. 



Color of dried colony white or buffy wliite. 



Type.—V.S.'NM. no. 43269. 



Type locality. — Station 3480, Amukta Pass, Aleutian Islands, 283 

 fathoms, black sand, rocky. 



Specimens examined. — Four fragments, three of which, including the 

 type, are believed to be male aud probably from the same colony; one 

 believed to be female. 



Remarks. — Stylaster gemmascens is recorded from such widely scat- 

 tered localities as Indian Ocean (Milne Edwards and Haime), vicinity 

 of Sulu Islands, 540 meters (Hickson and England), off Norway (G. O. 

 Sars, Broch, and others). I have examined specimens from Trondh- 

 jemsfjord, kindly supplied by the Riksmuseum, Stockholm, through 

 Dr. Sixten Bock. The United States National Museum possesses 

 specimens from Norway (no. 15275). Now the species turns up 

 along the Aleutian Islands, w^here the bottom water at 283 fathoms 

 may be estimated, from readings at other stations, as between 37° 

 and 38° F. 



There is no precise information on the type specimen said to be in 

 the Berlin Museum. Probably the Siboga specimen from off the 

 Sulu Islands is very nearly typical, but Hickson and England (1905, p. 

 13) give no information on the ampullae. The north Atlantic speci- 

 mens frequently have tubercles or blimt spines on the am.pullae, but 

 the walls are not strongly wrinkled as if badly shrmik, nor is the am- 

 pulla itself so prominent. So far as I can ascertain the siu-face of the 

 coenosteum is not finely echinate or ridged as in the Alaskan form. 



Quite apart from the improbability that a specific stock common to 

 the north Pacific, north Atlantic, and tropical East Indies would be 

 uniform, the fact remains that it is not homogeneous. Whether it is 

 ad\dsable to recognize geographical races depends upon viewpoint and 

 whether implications of zoogeography are to be seriously regarded. 



3936—38 2 



