4 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 4 



recognition. This applies particularly to gymnoblastic species, some of 

 which deteriorate so readily. The excellence and the extent of the col- 

 lection are worthy of comment. 



In the text, the distribution within the area is given for all species. 

 All new species, as well as all of those in which the gonosome has been 

 observed for the first time, are described and figured. In referring to 

 species already described, notation is made of the original description 

 and in many cases, another reference to a paper in which the descrip- 

 tion, the figure, or the synonymy is given more fully. No attempt has 

 been made to give a complete synonymy. 



I am indebted to my wife and to Miss Ursula Dale, an Honors 

 student in Zoology in the University of British Columbia, for the draw- 

 ing of the figures used. These figures show the same magnification 

 throughout — 20 diameters. 



To Captain G. Allan Hancock, who financed the expedition and 

 provided the facilities and who, with the Chief Officer, W. Charles 

 Swett, was tireless in doing everj^thing possible in the way of arrange- 

 ment to make the expedition a success, to the other biologists on board, 

 W. L. Schmitt, H. W. Manter, W. R. Taylor, J. Garth, and F. 

 Ziesenhenne, who were always on the lookout for useful material, and 

 to all the other officers and men in the ship's company, who lost no 

 opportunity to give assistance, I am under great obligation, which I 

 am happy to be able to recognize at this time. 



Distribution 



Of the 173 species listed, 73 are described as new, and in 5 other 

 species the gonosome has been observed for the first time. One new 

 genus is introduced. 



Of the 100 species previously described, 77, 77%, have been re- 

 ported from the North Atlantic; 52, 52%, from the eastern Pacific 

 coast of Canada and the United States; and 13, 13%, from the southern 

 portion of the eastern Pacific and from the waters adjacent to the 

 southern tip of South America. Thirty-seven species have been reported 

 from both the Atlantic and the North Pacific, 40 species from the At- 

 lantic but not from the North Pacific, but only 15 from the North 

 Pacific and not from the Atlantic. Of the 15, 7 were obtained from the 

 oceanic area, two of which were from this area only; 12 were obtained 

 from the coast of Mexico, 8 of these from the west coast of Lower 



