coe: nemerteans of west and northwest coasts. 241 



The ])resent known range of this widely distributed species is 

 thiis found to be from Massachusetts Bay to Greenland on the 

 Atlantic coast, and from Puget Sound along the whole Pacific coast 

 of Alaska, including its large bays and. islands, to the Aleutian 

 Islands, thence to the Commander Islands near the coast of Kam- 

 chatka, to Plover Bay, Siberia, and through the Bering Strait. All 

 these localities are characterized by very cold water, and the form 

 is not unlikely to prove a circumpolar, arctic form which extends 

 southward along the eastern and western coasts of North America 

 and eastern coast of Siberia to the latitude of 42°, 48°, and 55°, re- 

 spectively. This range will doubtless be further extended by future 

 collections. 



The species is apparently most abundant between tides, but 

 occurs at a depth of at least 85 fathoms. On the Atlantic coast the 

 species is found much farther south beneath the cold Arctic cur- 

 rents than on the shore between tides, as is the case with most other 

 arctic marine invertebrates. 



54. Amphiporus bimaculatus Coe. 



Proc. Wash. Acad. Sci., 3, p. 44, PI. 1, %. 4; PI. 5, fig. 10; PI. 8, 

 fig. 2; PI. 12, fig. 2, 1901 ; Harriman Alaska Expedition, 11, 



p. 44, 1904. 



PI. 2, fig. 21 ; PI. 18, figs. 116-118; PI. 22, figs. 154-156; Text- 

 figs. 10, 48. 



This form, which has previously been recorded from Puget Sound 

 and Alaska, has now been found on the coast of California. It may 

 be recognized by the following brief diagnosis : ^ — Body rather 

 short, stout, broad, flattened both above and below, tapering gradu- 

 ally towards both extremities (PI. 2, fig. 21). Head usually some- 

 what pointed, narrower than body, from which it is demarcated by 

 conspicuous nuchal grooves of remarkably large size and fluted or 



' Mr. J. F. Abbott, formerly of Stanford University, has kindly sent iiie a 

 colored drawing of the living worm and two sketches showing the i^eculiarities 

 of the characteristic nuchal groove. These are reproduced in PI. 2, fig. 21, and 

 PI. 18, figs. 116, 117. I am also indebted for interesting notes on the species 

 both to him and to Prof. C. B. Wilson, of Westfield, Mass. 



