47 



dary branch being tripartite. In the 3 r . d pair of gills (fig. 27) the division was considerably 

 more advanced. On the one side, the gill was 4 times completely dichotomically divided 

 with 8 terminal branches; on the other side the exterior secondary branch was only bipartite; 

 while the interior had 4 terminal branches, but was nevertheless not regularly dichotomic; 

 only the exterior tertiary branch having divided itself, and that so as to leave the interior 

 terminal branch simple as usual, while the exterior was forked, (the 5'. h dichotomy). A similar 

 irregularity in the dichotomical division of the gill appeared also in the following pairs of 

 gills (fig. 28 & 29); and it was observed here in both the primary halves of the gill. Hence 

 it seems that the gills in the present species may indeed, on the whole, be said to be divided 

 in dichotomic form; although the dichotomy is not everywhere strictly carried out. 



As above stated, 5 pairs of gills appears to be the normal number. Specimens are 

 however not seldom found, especially younger ones, with only 4 pairs of gills (see fig. 22 & 

 23); and in some very large specimens, I have sometimes found 6 pairs. But in every case 

 the gills take their beginning on the 4 1 ! 1 bristle-bearing segment; so that the first 3 segments, 

 as also those, coming after the 9 1 ! 1 , are always without gills. 



The pedal nodes (see tig. 31) are double, or 2 on each side of the segments, very 

 small and tolerably far from each other; the lower ones, about in the middle of the height 

 of the segment; the superior, near to the dorsal side. The rudimentary cirri are situated at 

 the end of the pedal bristles. The latter are very fine, and about half as long as the seg- 

 ment is wide. On the upper pedal nodes they, diverge to all sides; on the inferior, they 

 form a more regular fascicle. The origin of the gills is (see fig. 20 & 30) situated close 

 behind the superior pedal nodes, and inside of the rudimentary dorsal cirrus. 



The pedal bristles (fig. 34) are on the superior nodes simple, but of 2 different- sorts. 

 Some of them (b) are considerably thicker, and also shorter than the others, nearly thorn-like, 

 the point becoming suddenly of a very tender structure, and completely hyaline ; when very strongly 

 magnified, these bristles shew on one edge a slight indication of a peculiar armament of 

 hooked backward-turned teeth, similar to that described byKinberg in various Amphiuomides 

 from the tropical 'oceans. The other bristles on these pedal nodes (a) are more than double 

 as long, and considerably thinner, terminating in an exceedingly fine point, near to which the 

 bristle is on one side finely serrated. In the inferior pedal nodes, the bristles appear at 

 first glance similar to those last mentioned. On closer examination however it is remarked, 

 that most of them (c) exhibit at a short distance from the extremity a tolerably long, forward- 

 turned, close-lying side tooth, whereby they properly become forked; the end of the bristle, 

 from this side tooth, is very finely and closely serrated on one edge. Among the lower bristles 

 attached to this pedal node, some few (d) are remarked which are considerably stronger, 

 somewhat enlarged at the end, and here furnished with a short side tooth; the end of the 

 bristle is here much thicker and shorter than on the former, a little curved outwards, and 

 coarsely serrated on one edge. 



On the I 5 . 1 segment there are, besides the bristles described, on the upper pedal node 



