On the Lysianassa magellanica etc. 



15 



The truncal feet 1 ) of the first pair (fig. 13) are short, particularly strongly 

 built and subcheliform. Their length is about 15 millim. The 2 nd joint 2 ) 

 is the longest and the hand or 6 th is almost rectangular, rather smaller at 

 the lower end, with the fore edge somewhat bent and the back concave and 

 bearing about 9 clusters of bristles. Its lower end is obliquely hollowed 

 out, and in front of the notch is fastened a strong, sharp, crooked and 

 flexible claw. The 5 th joint which is triangular is shorter than the 6 th . Its 

 feet are without gill-sack and lamina to cover the eggs. 



The truncal feet of the 2 nd pair (fig. 14), which are also subcheli- 

 form, are finer and longer than the proceeding. Their length is about 30 

 millim., and the breadth of their 2 nd joint is 2 millim. The 3 rd joint is 

 scarcely half so long as the 2 ad , which is almost of uniform breadth and 

 somewhat bent back at the lower end. The hand or 6 th joint is shorter 

 than the 5 t!l , oblong and of almost uniform breadth, and obliquely rounded 

 off at the lower end. It has numerous long bristles, as have also the 

 joints already described. The claw is very small and hardly perceptible. 

 The lamina for covering the eggs (b) and the gill-sack (c) are fastened to 

 the 1 st joint or epimerum (a). The former is narrow and of uniform breadth, 

 and bordered with long bristles; the latter simple, of considerable size, 

 and almost kidney-shaped. One observes on it only a few small irregular 

 wrinkles which have probably arisen after death. 



The 3 rd and 4 th pairs of truncal-feet (fig. 15, right foot of 3 rd pair) 

 are similar to each other and about 24 millim. long. The 4 h joint is longer 

 than the 5 th , terminated obliquely at the lower end, where, at the obtuse 

 projecting point, it is provided with long bristles. The 6 th joint is about 

 the same length as the 4 th , almost uniformly broad, somewhat curved, and 

 at the back border provided witli bristles. The claw is strong. 



The truncal-feet of the 5 th — 7 th pairs (fig. 16, the 6 th pair, right foot) 

 bear a close resemblance to eachother, and differ from all the preceeding 



') We here adopt the denominations proposed by T. Thorell, (OfVers. af 

 Kongl. Vetensk. Akad.-s Forh 1804. pag. 9 J according to which that part of the body 

 of the Crustacea, which is commonly called thorax, is denominated trunc (truncus), 

 and that part, which by other writers is called abdomen, is denominated tail (cauda). 



2 J The joint which we call the 2"' has in general been considered as the 1 st . 

 We consider that that part, to which the gill-sack and lamina for covering the eggs 

 arc attached, is the first, although it may lie joined to the epimerum, or perhaps more 

 correctly speaking (according to Spence Bate) constitutes what is called the epime- 

 rum. The gill has no doubt an insertion similar to that of the Podophthalmia. 



