76 CRUSTACEA MALACOSTRACA. IV. 



joint in reality consists of two joints completely fused, and that these two joints are well separated in Neba- 

 lietta and Nebaliopsis. It is now generally admitted that the Nebaliacea are more related to the Mysidacea 

 than to any other order; furthermore it is known that in Mysidacea and Isopoda Asellota the sympod of 

 the antennae consists of 3 joints, and that the exopod is more or less developed, furthermore that beyond the 

 sympod the 3 proximal joints of the endopod are very different in aspect from the flagellum, so that in the 

 Asellota with the exopod or squama much reduced the peduncle of the antennae consists of 6 distinct joints. 

 We shall now see that the same parts are found in Nebalia. What the authors considered to be the first joint 

 consists of two well separated joints (fig. 10 a, / and 2), the first being in Nebalia well chitinized on most 

 of its outer side and separated from the second by a narrow membrane. Near the end of the lower margin 

 of third joint in Nebalia is on the outer side an insignificant, low elevation, but in Nebaliella antarctica is 

 found, as figured by Thiele (1904), an oblong protuberance, which in my young specimen is well marked 

 . off and certainly is the reduced squama ; in several Asellota the squama is also quite small and of similar 

 shape. At the end of third joint the fourth is represented by a transverse, movable, well chitinized plate 

 (fig. 10 a, 4) ; also in Mysidacea and Asellota this joint is short. Fifth and sixth joints are, as already said, 

 fused in Nebalia, well separated in Nebaliella and Nebaliopsis. 



The Maxittulce (fig. 10 b) are rather easy to investigate. Each consists of a proximal broad part, 

 the sympod, and an extremely long "palp", the endopod. The sympod consists of 3 joints; first (i) and third 

 (3) joints each with a lobe on the inner side, while second joint (2) has none, completely as in Mysidacea, 

 Isopoda, etc. The chitinized elements of joints and lobes are seen in fig. 10 b; the membranous skin between 

 them has a greyish shading. An exopod is wanting in this order. 



The Maxillce (fig. 10 c) consist of a sympod with a 2-jointed endopod and an unjointed exopod. 

 The sympod consists in other orders of Malacostraca of 3 most frequently well separated joints, with a lobe, 

 frequently bifid, from second and from third joint, but never any lobe from first joint. In Nebalia the 

 plate of first joint (/) is united with that of second joint, as there is no distinct line between them; the 

 lobe from second joint (I 2 ) has its chitine bipartite, while the lobe from third joint (/ 3 ) is only bifid. 



The thoracic Legs (fig. lod). Only sympod and endopod need to be mentioned. The sympod 

 consists according to authors of .2 joints, but it is in reality 3-jointed. The first joint can be seen by a strong 

 pocket-lens in a Nebalia, when the carapace is taken away and the epipods pushed aside; the joint is short, 

 but its outer side is well chitinized and well marked off both from the following joint with the epipod and 

 from the tergite of the segment; seen from behind this joint (fig. 10 d, /) is a transverse triangle. Second 

 joint (2) has a kind of low lobe on the inner side, and this lobe is always distinctly cleft rather little behind 

 the distal end. As to third joint (j) it is difficult to decide where it terminates and the endopod begins. In 

 Nebalia one can as a rule count 5 joints in the endopod, the two or three most distal marked off by a line 

 across the leg, while between the more proximal joints this line is distinct only towards the inner margin. 

 But in a couple of cases I counted with certainty 6 joints (fig. 10 d) ; the sympod was then considerably 

 shorter, as an additional, more proximal transverse line is visible near the inner margin and situated opposite 

 the insertion of the exopod. - - In the penultimate legs of Paranebalia I found features very valuable for 

 the understanding. Near the inner margin of the narrow endopod of the leg five very small, narrow and 



