631 



than the superior, and somewhat stronger in male than in female, last joint 

 of the peduncle the longest, flagellum much shorter than that joint, and 

 biarticulate, last articulation extremely small. Anterior gnathopoda with the 

 meral joint greatly instricted at the base, and forming below a rounded, 

 setiferous lobule, carpus rather large and expanded, propodos about the length 

 of the latter, and gradually widening distally, palm somewhat oblique and 

 defined below by an obtuse angle. Posterior gnathopoda in female much 

 stronger than the anterior, basal joint forming at the end outside an acute 

 lappet, meral joint produced below to a long acuminate projection, carjjus 

 very small, propodos large and expanded, rounded oval in form, with the 

 palm arcuate, and defined by a short dentiform projection, dactylus strong and 

 curved ; posterior gnathopoda in male still more powerfully developed, meral joint 

 less produced than in female, propodos exceedingly large and somewhat curved, 

 oblong oval in form, with numerous, partly ciliated setae below, palm not 

 defined, but produced in front to a broad, slightly denticulated lobe, below 

 which is a short spiniform projection, dactylus extremely strong and sharply 

 bent at the base, impinging, when closed, against the lower face of the 

 propodos. Pereiopoda of exactly same structure, though the 2 anterior 

 pairs, as usual, curve in a manner opposite to the 3 posterior ones, basal 

 joint in all narrow linear, meral joint comparatively short, carpal and pro- 

 podal ones elongated, dactylus very strong falciform. First pair of uropoda 

 with the inner ramus very slender and linear, being twice as long as the 

 outer, both edged with short spines; 2nd pair forming on each side an oval, 

 unarmed lamella, partly covered by the telson; the latter evenly rounded 

 and quite smooth. Colour light yellowish. Length of adult female 4 mm., 

 of male about tlie same. 



licmarks. — This form was first described by Bruzelius from the coast 

 of Bohuslan, and was subsequently recorded by Sp. Bate under another name, 

 viz., Cyvtophium Durwini. It is the type of the present genus. 



Occurrence. — I have met with this form rather abundantly in several 

 localities of the west coast of Norway, as also in the Trondhjemsfjord, in 

 depths varying from 20 to 50 fathoms, especially where the bottom is muddy 

 and intermingled with small pebbles and sand. Boeck also records it from 

 tlie Christianiafjord and from the Nordland coast. In spite of its small size, 

 it is easily ol)served Ijy its light yellow colour, and, when kept alive in a 

 ves.sel wiHi a portion of the bottom-material, is generally found to rest 

 nearly motionless, firmly attached by its strong pereiopoda to some small pebble 

 or shell, the antennae spread out to each side. AVhen disturbed, it starts 

 away rather rapidly, but very soon again gets hold of another particle on 

 the bottom. 



