of the North Atlantic and of North-Western Europe. 685 



external seta there is ranged on each margin a short series of extremely delicate 

 cilia (PL LX., fig. 23) ; these are very flexile, and are set for the most part nearly 

 at right angles to the stem, resembling somewhat the patch of loose plumes at the 

 base of the vane of a feather ; these cilia are so small and delicate that they are 

 often seen with difficult}^, even with a magnifying power of 400 diameters. The 

 basal joint of the antennule shows, irregularly scattered near its surface, a number 

 of lenticular bodies overlying patches of red pigment, perhaps rudimentary visual 

 organs* (PI. Lxv., fig. 12a.) Frontal tentacle in the female linear, in the male, 

 dilated at the apex. Natatory branch of the antenna seven-jointed, the first joint 

 more than twice as long as the remaining jointed portion ; secondary branch 

 bearing five apical setse, of which in the female one is longer than the rest, while 

 in the male (fig. 14), two are much elongated, one being thrice, the other four times 

 as loilg as the shorter three ; in addition to these sette there is in the male a short 

 sickle-shaped apical appendage. Male copulative organ (fig. 22) narrow, elon- 

 gated, slightly dilated towards the apex, crossed by oblique transverse lines, 

 and having an ejaculatory duct opening at its distal end. Length, 1-4 mm. 



Habitat. — Taken abundantly by Dr. John Murray, in Loch Etive, Scotland, 

 by the tow-net at a deptli of 50 fathoms. 



Distribution. — Rare in Drobak Fjord at a depth of 100—200 fathoms; very 

 abundant among the Lofoten Islands down to 300 fathoms (Gr. 0. Sars). This 

 species is recorded by Dr. Claus (under the name of Paraconchoecia gracilis) as 

 having been taken in a depth of 1500 metres, in lat. 37° 45' N., long. 13° 38' W. 



2. Conchoecia borealis, G. 0. Sars. 



(PI. LXi., figs. 9-19.) 



1865. Conchoecia lorealis, . . Sabs, G. 0., " Oversigt af Noi-ges marine Ostra- 



coder," p. 119. 



Shell of the female seen from the side, elongated, subquadrangular, higher 

 behind than in front, greatest height equal to nearly half the length, dorsal 

 margin straight, but showing a marked indentation near the middle, ventral 

 slightly sinuated in the middle ; anterior extremity gently convex, with a subacute 

 rostrum of moderate size, and a slightly excavated sinus ; posterior sub-truncate, 

 rounded off belovp^, and obtusely angulated above. Seen from above, elongate- 

 ovate, about thrice as long as broad, widest near the middle, broadly rounded or 

 sub-truncate in front, tapered and acutely-pointed behind. Surface of the valves 

 densely cross-hatched with quadrangular reticulations (fig. 19) which are arranged 



* These are called " ganglia" by Dr. Claus, but if they are purely nerve-centres it is difficult to under- 

 stand the meaning of the red pigment-masses associated with them. 



TRAUS. EOT. DTJB. SOC, N.S. VOL V., PAKT. XH. 5 J) 



