280 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.39. 



the plate, and both appendages are inverted. If the figure be turned 

 so as to bring the appendages into their proper positions, then the 

 "maxillary palp," as Gadd designates it, is in front of (anterior to) 

 the maxilla, which is not where such a palp belongs. The second 

 figure (pi. 1, fig. 23) represents the mouth-parts of a female of E. 

 sieholdii. 



This figure is turned down on its side, and must represent the left 

 side of the mouth parts, as seen in a somewhat diagonal view, partly 

 ventral and partly lateral. Here the "maxillary palp" is behind 

 (posterior to) the "maxilla," and there are two "first maxillipeds," 

 exactly alike and attached one behind the other, which is rather 

 difficult to explain. 



Moreover the basal joint of the true mandible (which Gadd calls a 

 maxilla) is not represented at all, but in the figure the appendage 

 looks as if it were attached directly to the upper lip. In the face of 

 such radical mistakes we can only conclude that Gadd's observations 

 were inaccurate, and hence his arguments lose their power. 



That this first pair of appendages are true mandibles is evidenced 

 by the following facts : 



1. They are the first or anterior pair, are situated in just the 

 right position with reference to the upper lip, and correspond exactly 

 in all the genera belonging to the Ergasilidse. 



2. If they are maxifise, then the mandibles are lacking, a condi- 

 tion occurring nowhere else among the parasitic copepods and con- 

 trary to the facts established by degeneration. 



3. In the great majority of species they project into the mouth 

 under the upper lip (see figs. 9 and 10). They are thus partially, and 

 in some species almost wholly, inclosed, a condition which would be 

 anomalous for the maxillae, but just what we should look for in 

 mandibles. 



4. Comparison with free-swimming forms shows that the organs 

 under discussion are analogous in structure and position with the 

 mandibles of the latter. 



5. In genera like Taemacanthus and AncJiistrotos, where all the 

 mouth-parts are present, we are certain that this first pair must be 

 mandibles. If so, they are also mandibles in the other genera. 



The maxillary hoolcs. — These are present only in the genera belong- 

 ing to the subfamily Taeniacanthinse, where they have been described 

 by Claus (1864), Heller (1865), Sumpf (1871), Bassett-Smith (1898), 

 and Brian (1906). Each of these authors has given them a different 

 name, although the general meaning of the names is the same. (See 

 table, p. 278.) 



Heller and Brian state positively that these appendages correspond 

 to the ones found in Caligus and Le'peojjhtheirus, and the other 

 authors tacitly agree to this by giving them the same name that each 



