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PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. XXVIII. 



varies greatly in the different species as well as in the genera. In 

 Galigus curtus there is a long rod on either side of the mid line, the 

 two being approximately parallel to the very tips where they bend in 

 suddenly together and are united for a short distance along the mid 

 line (m, fig. 8). Connected with this united portion are three short 

 transverse rods (t). All of these rods are narrow and cylindrical in 

 shape (Pickering and Dana, 1838). 



In Caligus rapax there is a large V-shaped rod at the base of the lips 

 (v'), and another (v") at the tip, the bases of the two Vs being toward 

 each other and their sides being connected by a series of short, almost 

 spherical rods (s, fig. 9). The V-shaped pieces are strongly flattened 



FIG. 8.-VENTRAL SURFACE OF THE MOUTH TUBE OF FlG - 9--VENTRAL VIEW OF THE MOUTH TUBE OF 



an adult Caligus curtus. (After Pickering Caligus rapax in a late chalimus stage. 



and Dana.) m, longitudinal central rods r - R0D 0N lateral margin of lower lip; 



IN FRAMEWORK OF LOWER LIP; t, TRANSVERSE S > V '> V " SH0RT EODS FORMING THE FRAME- 



R0Dg WORK OF THE LOWER LIP. 



and much wider than thick, and might well be called laminae instead 

 of rods. 



The membrane forming the upper or dorsal portion of the mouth 

 tube may be called the upper lip. Like the lower lip, it has a chitin 

 rod (r', lig. 10) along either lateral margin, but in this instance, instead 

 of being connected at the tip by short transverse rods, the chitinous 

 edge is continuous around the anterior margin (fig. 6). 



The proximinal ends of the rods are enlarged and flexed, but not as 

 sharply as those of the lower lip, and to them are attached muscles for 

 moving the lip. There is no central framework in this dorsal mem- 

 brane, but the latter is stretched from one marginal rod to the other. 

 In Caligus cartas and Lepeophtheirus edwardsi the anterior portion of 

 the chitinous margin is bent back in the form of a semicircle, into 

 which fits a more or less circular flap (f) of soft membrane whose front 



