W. H. Leigh-Sharpe 
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cylindrical, and swollen or enlarged at the distal ends 1 . They are the 
principal organs of attachment. When first they arise in the meta- 
nauphus stage they are clawed appendages similar to the maxilhpedes. 
In the free-swimming or first Copepod stage, when the larva attaches 
itself to the host, the 2nd maxillae are fastened to the proximal end of 
the frontal filament. In the female this union of filament and maxillae 
Pig. 3. Leinatopoda scyllicola. The appendages. A, the first antenna, or antennule; 
B, the second antenna: Ex. the exopodite, En. the endopodite; C, the mandible; 
D, the first maxilla: Ex. the exopodite, En. the endopodite. 
becomes permanent throughout life, and the two fuse thoroughly until 
all that is left of the filament is the bulla or button which joins the tips 
of the maxillae and serves to anchor them firmly in the tissues of the 
host (Fig. 4 a). The parasite once attached becomes incapable of 
change of position, but the length of the “arms,” as the two maxillae 
are often called, which are separate to their tips allows of a considerable 
1 In L. galei, Wilson in one place gives the 2nd maxillae as long as the trunk, but most 
of the authors cited in the references give two-thirds the length of the trunk. 
