14 ARKIV FÖR ZOOLOGI. BAND 14-. NIO 10. 



and giving off a duster of frontal processes, which are soft 

 and many lobed. On the ventral surface on either side a 

 long soft pointed process extends diagonally outward and 

 forward from the bases of the frontal processes. Just be- 

 hind these and also on the ventral surface is the pair of 

 profusely branched soft horns, which anchor the head to the 

 retina. The base of each horn is wide and strongly flattened 

 dorsoventrally, the two apparently fused across the midline. 

 The rami are also wide and similarly flattened, and most of 

 them are dichotomously branched. The fourth segment is 

 armed with two pairs of large chitin horns, one pair lateral 

 and one ventral. 



Each lateral horn is biramose while the ventral horns 

 are triramose. Behind the horns the fourth segment is nar- 

 rowed into a short chitinized neck, which joins the trunk 

 at a right angle a short distance back of its anterior end. 

 In the original type specimen this junction was not on the 

 midline but removed a little to one side. The same is true 

 of one of the present specimens, but in the others the neck 

 joins the trunk exactly on the midline and thus preserves 

 the symmetry. 



Trtmk triangulär, the dorsal margin nearly straight, the 

 ventral margin strongly convex, these two forming the sides 

 of the triangle and coming together in a rounded knob in 

 front of the base of the neck. The posterior margin or base 

 of the triangle is also nearly straight. The egg strings are 

 attached on either side in front of the posterior margin and 

 close to the dorsal surface. They do not stånd out as straight 

 laterally as in the original specimen, but are inclined at an 

 angle of about 45 degrees, and are loosely coiled. The head 

 and thorax are twisted through an angle of 90 degrees, so 

 that the ventral surface faces the side of the trunk. 



The antennae and mouth parts are reduced to knobs, 

 the former on the dorsal surface, the latter on the ventral 

 surface, just behind the bases of the frontal processes. The 

 first two pairs of swimming legs are close together behind 

 the flattened bases of the soft horns; the third pair is half 

 way between the soft horns and the chitin horns of the 

 fourth segment; the fourth pair is between the bases of the 

 ventral horns on the fourth segment. The first two pairs 

 are biramose, the rami indistinctly jointed; the third and 



