422 Dr. H. J. Hansen on the Morphology of the 
the Calanidx are “ phylogenetically the oldest forms ” among 
the Eucopepoda) that the rudiments of the first and second 
pairs of maxillipedes arise entirely independently one of the 
other ; consequently they each correspond to their own pair of 
appendages, and not to the cuter and inner branches of one and 
the same parr. Owing to the peculiarities in the structure 
and the relative position of the maxille and maxillipedes in 
the free-living and parasitic Copepods I regard the maxilla 
as homologous with the maxillule, the first pair of maxilli- 
pedes as homologous with the maxilla in the Malacostraca, 
and the second pair of maxillipedes as homologous with the 
maxillipedes (e. g. in the Amphipods), and, among other 
things, as exhibiting the same tendency towards mutual 
fusion. 
12. In Argulus the swimming-feet consist very distinctly 
of a three-jointed shaft and two branches (Kyéyer). ‘The 
basal joint of the shaft is much shorter than the second and 
somewhat shorter than the third. 
13. It follows from §§ 7-12 that we must assume the 
presence of three segments in the stem of all cleft appendages in 
Crustacea to be a primary condition; and this number has 
distinctly persisted, at any rate in the cases quoted. 
b. MALACOSTRACA. 
a. Leprosrraca (§§ 14-17). 
14. Nebalia must be assigned to the Malacostraca (Claus), 
and in many respects it approaches the Mysidew, while the 
Euphausiide, on the contrary, are very far removed from it 
(vide § 26). 
15. In Nebalia bipes the shaft of the second pair of antenne 
consists not of three (Claus) but of five segments, and the 
fifth segment shows a tendency to be composed of two (Claus), 
which are well separated in Vebaliopsis ; after removing the 
shield the first segment may be easily found by the aid of a 
good dissecting-microscope ; this segment is somewhat short, 
but well marked off; the fourth segment is conspicuously 
marked off on the outer side, but is very short. 
16. The limbs of the thorax consist not of seven but of 
nine segments. In Nebalia bipes we find on the outer side of 
the limb at the base a somewhat short but very distinct 
segment; after this there come the segments with the epi- 
podite and exopodite, and finally the remainder of the limb 
shows three distinct incisions on the inner margin and three 
joints. (All these details are best seen in appendages laid 
