428 Dr. H. J. Hansen on the Morphology of the 
maaille of authors) in the Malacostraca, and the labium as 
homologous wiih the mawillipedes and agreeing in many 
respects with these appendages in the case of the group men- 
tioned. ‘he submentum is homologous with the first segment, 
which is fused in the Gammarine, and the mentum with the 
second segment, which in the Hyperine is likewise fused. 
At the tip of the mentum we find a segment, produced on 
each side into four lobes, which, as may be seen with sufficient 
clearness, belong to two lobes, each of which is cleft ; and 
these I regard (among other reasons on account of a compa- 
rison with Orthoptera and Amphipoda, although I cannot 
bring forward any cogent proof derived from the skeletal 
parts) respectively as a lobe from the second segment (the 
innermost cleft lobe) and as the third segment of the labium 
with its cleft lobe: the palpus arises from the outer side of 
the third segment. 
32. The hypopharynx is conspicuous, almost rectangular | 
in shape, slightly emarginate in front, and homologous with 
the hypopharynx (paragnathi) in the Malacostraca. The 
organs which are termed “paraglosse”’ by authors have 
nothing to do with the hypopharynx; in the skeleton of the 
head they are articulated at the bottom of the hypopharynx 
and have a somewhat complex structure, with an external 
process like a small single-jomted palpus, and towards the tip 
a distinct tendency to cleavage into two lobes. I regard 
these “ paraglosse”? as homologous with the maxillule of 
Crustaceans (a supposition which is strengthened in the 
highest degree by their structure in Japyx and the Collem- 
bola, vide § 39) ; the essential difference in Machilis consists 
in the fact that they are situated somewhat nearer to the 
median line and lie partly in front of the hypopharynx; yet 
in Argulus, according to Claus, the maxille are enclosed 
together with the mandibles in the suctorial tube, and are 
consequently placed before the hypopharynx. (If a carcino- 
logist should raise the objection that im the case of Apseudes 
we find a lobe resembling an appendage upon the hypopharynx, 
we must reply that in Apseudes only the elongated outermost 
anterior angles are segmented off in a secondary fashion, 
while in Machilis, Japyx, and the Collembola the maxillule 
arise from the skeleton of the head at the base of the hypo- 
pharynx, which in these animals is not cleft towards the tip.) 
33. The thoracic appendages have an elongated coxa, 
which is attached to the body by means of a small and for 
the most part firmly chitinized segment, which is freely 
movable, and which on account of its position and shape we 
must regard as the first jomt of the leg. I regard it as homo- 
