86 H. J. HANSEN. 
outer lobe of both maxillulee their spines, while lacinia mobilis, 
etc., had disappeared ; in the other specimen only a little of 
the dark colour on the end of the mandibles and the spines 
on one of the maxillule were preserved. 
Giard and Bonnier have shown that in the Bopyrine the 
females have the first joint with its epipod and second joint 
of the maxillipeds strongly expanded and adapted for pro- 
ducing a current of water. Schiddte and Meinert pointed out 
that in the Algine (Aga, Rocinela) the marsupial plates 
cover the entrance to the mouth, so that egg-bearing females 
cannot take any nourishment ; females with marsupium have 
never been found on fishes, but are not uncommonly captured 
with dredge or trawl. In 1890 the present author showed that in 
the Aigine and in all other Cymothoide, sens. lat. (Cirolana, 
Corallana, Aiga, Nerocila, Cymothoa, etc.) the adult 
females have the two proximal joints—with the epipod—of the 
maxillipeds strongly expanded and evidently adapted for the 
same purpose as the corresponding part in female Bopyrine, 
but in no form any real reduction of the other mouth-parts 
was observed. In several genera of Spheromide we have a 
similar expansion of the proximal half of the maxillipeds, but 
their distal half and all the other mouth-parts are reduced in 
a most peculiar way, and so strongly that the animals cannot 
take any food at all. Such metamorphosis of the mouth-parts 
in females carrying brood is, as far as I know, without 
parallel, not only among other Arthropods, but among animals 
of every other series. 
Finally, there is the question as to the systematic value and 
biological bearings of this metamorphosis. In Limnoriine, 
Plakarthriinez, and probably in all platybranchiate Sphero- 
minee (I have examined females with brood of representatives 
for the four sections constituting this group) the mouth-parts 
are similar in both sexes; in all these animals the end of 
abdomen has either a rather shallow notch (Plakarthrium) 
or a notch not visible from above (Campecopea) or, gene- 
rally,no notch. The hemibranchiate Spheromine are naturally 
divided into two sections, Spheromini and Cymodocini; in 
