502 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. XXVIIl. 



\;ii'ios o-roatlv in i\\o dillVrciit species as well as in the genera. In 

 Cdlnjiis cinitis thei'e is a lon^- rod on either side of the mid line, the 

 two beino- approximately inirallel to the very tips wh(>re they hend in 

 suddenly tog-ether and are united for a short distance along the mid 

 line (m, fig. (S), Cc^nu^cted with this united portion are three short 

 transverse rods (t). All of these I'ods are narrow and cylindrical in 

 shape (PickcH'ing and Dana, 1838). 



In Cdl ! (J it-^ I'djxi.f i\\QV(i 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, tig. 1>). The V-shaped pieces are strongly flattened 



Fig. 8. — Ventral surface of the moitth tube of 

 AN adult Caligus curtus. (After Pickering 

 AND Dana.) m, longitudinal central rods 

 IN framework of lower lip; t, transverse 



RODS. 



Fig. 9. — Ventral view of the mouth tube of 

 Caligus rap.ax in a late chalimus stage. 



r, rod O.N LATERAL MARGIN OF LOWER LIP; 

 S, v', V", SHORT RODS FORMING THE FRAME- 

 WORK OF THE LOWER LIP. 



and nuich wider than thick, and might well be called lamina? instead 

 of rods. 



The meml)rane forming the u]iper or dorsal portion of the mouth 

 tut)e may be called the upper lip. Like the lower lip, it has a chitin 

 rod (r', tig. 10) along either lateral margin, l)ut in this instance, instead 

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

 edge is continuous around the anterior margin (fig. 0). 



The proximinal ends of the rods ai-e enlarged and flexed, but not as 

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

 moving the li}). There is no central framework in this dorsal mem- 

 l)rane, but the latter is stretched from one marginal rod to the other. 

 In Caligun cnrtu-s and Lepeophtheirux edwarchl 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 



