268 A Parasitic (Jopepod 
play of movement around this fixed centre which is performed by the 
maxillipedes. 
The bulla or button is derived from a hardened secretion of the 
frontal gland; it is shaped like a collar stud whose upper surface is 
concave or pateriform, and indeed its function is a somewhat analogous 
one. Its details are pretty, and, as far as I know, have not been figured 
for any species previously. 
Fig. 4. Lernaeopoda scyllicola. The appendages continued. A, the distal ends of the 
second maxillae under a high magnification; a. the swollen tips of the maxillae, 
b. the bulla. B, the maxillipede; b. basal joint, t. terminal joint, m. muscle, h. hook. 
The Maxillipedes (Fig. 4 b) are clawed appendages situated between 
the bases of the 2nd maxillae (Fig. 5), and consist of a basal joint well 
supplied with powerful muscles which move the terminal clawed joint, 
and flex it down against the inside of the basal joint, which is long and 
slender and provided on the inner side with two rounded cushions 
covered with papillated spines. Between these cushions is a large 
curved hook (absent in L. galei where the basal joint is stout). The 
terminal joint is rather slender and terminates in a long, abruptly- 
