594 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
Branchial sac without folds, but with many transverse and longi- 
tudinal vessels dividing the wall of the sac into square meshes. Each 
mesh more or less irregularly subdivided into stigmata by slender 
vessels. One of these forms a spiral (though not usually of over 1| to 
2^ turns) arising from a transverse vessel and winding toward the 
center of the mesh. It is supported by a few irregular radial vessels, 
which at the same time divide the space up into separate stigmata. 
Spirals arise only from alternate transverse vessels. Those arising^ 
from the same vessel opposite each other (hence in adjacent vertical 
rows but in the same horizontal row) curve in opposite directions; 
in the same vertical row all curve alike, either in a right- or left- 
handed direction. In many of the meshes the spiral is so rudi- 
mentary or distorted that its spiral nature is practically^ lost, the 
mesh being apparently occupied only by a few irregularly placed 
vessels. Internal longitudinal vessels present, corresponding in num- 
ber to the rows of meshes, but they are very slender and often inter- 
rupted midway between the supporting papillae (see PI. 65, fig. 123). 
These supporting papillae are very long and slender and taper to the 
upper end where the vessel is attached. 
The intestine and stomach are too much mutilated to permit of 
tracing their course. The stomach is short and wide with numerous 
short irregular convolutions or areolations in its walls. The proximal 
part of the intestine is much curved and of large diameter; the rectum 
straight and the margin of the anus has a number of irregular rounded 
lobes. 
The gonad is likewise too much mutilated to determine its form and 
extent, though portions of both the ovary and the testis remain in the 
bend of the intestinal loop. The ovarian part which remains consists 
of a rather large irregular mass of eggs, the male part of several rather 
compact though much branched masses which divide into numerous 
very small lobules in an irregular manner. 
The animals of this genus are generally highly colored during life, 
but these colors do not persist in preserved specimens. 
This species has hitherto been recorded only from the Arctic Seas, 
and though widely distributed, appears to be quite rare. Hartmeyer 
(1903) gives the following localities: Spitzbergen, Kara Sea, Davis 
Straits, and the east coast of Greenland. Depths, 66 meters to 250 
fathoms. 
The single New England specimen, which the writer has identified 
