652 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. XXVII. 



Ventral surf ace (fig. 35). — Both pairs of antennae are relativeh' small 

 and weak, but are fairly well armed with hooks and spines. The 

 anterior and lateral hooks on the basal joint of the first pair are slender, 

 but the spine on the posterior border is above the average size. 



The terminal portion of these first antenna' is slender and does not 

 project beyond the lateral hook (fig. 36). 



The basal joint of the second antennje is as long as, and much thicker 

 than, the two terminal joints, and the latter are attached obliquely to 



/ ^ C il 111 111. 



-Dorsal surface of a female argulus trilineata. 



one of its distal corners, so that the two portions of the antenna? stand 

 nearly at right angles to each other. 



The basal joint carries a stout spine on its posterior margin just 

 where it joins" the head, and two long, slender spines on the ventral 

 surface at the distal end. The second joint has a single long spine on 

 its anterior border at the distal end, while the terminal joint carries 

 five or six large and stout spines. The spines along either side of the 

 mid line of the body opposite the bases of the antennae, those on the 



