16 



W. LlLLJEBORG, 



in having the 2 nd joint strongly expanded, and in being directed forwards. 

 The foot of the 6 th pair here represented is 24 millim. long. The 5 th pair, 

 as may he seen in fig. 1, is distinguised by having the 1 st joint larger, 

 and the back part somewhat higher than the forepart, which is almost semi- 

 circular. The second joint is shorter, and has the posterior spreading 

 portion almost semicircular. In those of the 6 th pair this joint is rounded 

 ovally, and the border rough with indentations or notches. These inden- 

 tations are only slightly apparent in the 5 h pair. At the base of the la- 

 mina for covering the eggs, attached to these last mentioned feet the fe- 

 male genital aperture is very clearly apparent. The 7 th pair of truncal-feet 

 differ from both the preceeding in having the 2 nd joint longer and oval, 

 with small but clearly visible indentations in the back border. 



Each pair from the 2 1,1 to the 5 th inclusive is provided with laminae 

 for covering the eggs, all of the same form as that, which is represented 

 in our plate, and which belong to the 2 nd pair: the 6 th and 7 rh pairs are 

 destitute of this appendage. In the 2" d , 3"' and 4 th pairs the gill-sack is 

 of the same form (fig. 14 c). In the 5 th and 6 rh pairs it presents the same 

 form (fig. 17), but differs from the preceeding in being of a firmer structure, 

 and having a caecum-like appendage (b) containing granulated matter, con- 

 sisting of fat globuli and other formative particles. In the 7 th pair this 

 appendage is wanting, but in other respects its gill-sack is similar to that 

 of the foregoing pair. 



The tail-feet of the first 3 pair's, or so-called swimming-feet, are 

 of the usual form (fig. 18, l sl pair, right foot) and are similar to eachother 

 excepting that they diminish in size, so that the 3" pair are shorter than 

 the foregoing. They consist of a strong, oblong stem, (a) tapering towards 

 the lower end, and two terminal branches (b, b) tapering gradually to a point, 

 longer than the stem, composed of a great number of joints, and on both 

 sides provided with long ciliated bristles. The l sl pair are 19 millim. long. 



The tail-feet of the last 3 pairs (i. e. the 4 th , 5 th & 6"') are as 

 usual formed for leaping, and consist of a stem and two simple terminal 

 branches without swimming-bristles. The 2 first pairs are as nearly as 

 may be similar to one another, but are longer and have their terminal 

 branches more pointed than those of the 6 th pair. Those of the 4 rh pair 

 (Fig. 19, right leg, outer side) are somewhat longer and slenderer than 

 those of the 5 t!l ; their length is about 14 millim. Along the outside of the 

 stem there is a raised ridge, and a similar elevation runs along the middle 

 of both terminal branches both on the outer and inner side, though higher 



