84. H. J. HANSEN. 
ment and generally nothing remains. The lobes of the 
maxille (fig. 2c) have lost all their numerous sete found in 
the male (fig. 1 d) and in immature specimens, and the bifid 
outer lobe has been shortened. Besides, all these mouth- 
parts have the muscles considerably or much reduced ; but 
the muscles to the mandibular palps, still shaped as in the 
males, have been preserved. The hypopharynx has been very 
reduced (fig. 2 e), being only about half as large as in the 
male (fig. 1f). The maxillipeds are still more interesting ; in 
the female with brood (fig. 2d) the four distal jomts have 
been reduced in size, especially the lobes are much shorter 
and have lost all the setze found in other specimens (fig. 1 e) ; 
the lobe from second joint has lost its distal setee, but the two 
proximal joints with the epipod are, on the contrary, ex- 
panded to such a degree that their joint surface is between 
twice and three times larger than in the male of the same 
size; some of the muscles in the palp have been reduced in 
size and all are lighter in aspect, while the musculature 
moving the expanded proximal portions is well developed. 
As in Cymothoidz the first joint of the female maxillipeds 
has a thin free ciliated plate directed backwards ; the second 
joint is shorter than in the male, but much expanded out- 
wards, and the free outer margin furnished with long plumose 
setee not found in the other sex. We can therefore not say 
that the mouth-parts as a whole have been reduced in adult 
females; the proximal half of the maxillipeds has, on the 
contrary, been developed as a special instrument for produc- 
ing a current of water through the marsupium, while the 
distal half of the maxillipeds and the outer mouth-parts, the 
mandibular palps excepted, have been strongly reduced, and 
are even unfit for use. The direction of the current must, of 
course, be observed in living animals; judging from various 
reasons, I am, however, convinced that it goes from behind 
forward. 
The genera in which the females with brood have the mouth- 
parts metamorphosed are enumerated above. The altera- 
tions are essentially as in Cymodoce, but it must be men- 
