86 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.53. 



and dorsal; horns chitinous and profusely divided, the tips of the 

 subdivisions usually somewhat swollen. Neck about the same diame- 

 ter throughout and often showing transverse wrinkles. Trunk con- 

 siderably enlarged and elongated, the portion representing the geni- 

 tal segment of about the same diameter, the abdomen tapering to a 

 bluntly rounded end. In the full-grown adult there is no groove 

 or other indication of the point of junction of the genital segment 

 and abdomen as there is in immature specimens, but the two are in- 

 distinguishably fused and are bent into the form of the letter S . 



A pair of minute anal laminae can be easily detected in half- 

 grown specimens, and they persist in the mature adult, each being 

 tipped with a single seta. The egg strings are voluminous and each 

 is drawn into a loose and irregular coil which, if straightened, would 

 be several times the length of the entire body; eggs minute and 

 strongly flattened. 



Two pairs of antennae on the dorsal surface of the head as in all 

 the Lernaeidae, the first pair three-jointed, with a tuft of setae at 

 the tip, the second pair two-jointed, the joints about the same size, 

 the terminal one bearing a stout chela. Proboscis strongly pro- 

 trusible; when fully extended (fig. 101) it forms a bluntly rounded 

 cone on the front of the head, pointed backward parallel with the 

 axis of the neck, and carrying on its tip the two pairs of maxillae. 

 In preserved specimens the proboscis is usually withdrawn so com- 

 pletely that it pulls in with it the whole front of the head and causes 

 the latter to assume a cup shape, as represented in Emerton's excel- 

 lent figures (figs. 98-100). 



The muscles which control this proboscis are evidently arranged 

 like those in Peniculvs (fig. 2), so that the mouth tube proper can be 

 withdrawn a long distance. At the tip of the mouth tube are the 

 two pairs of maxillae, the first pair {mx, fig. 103) short finger-like 

 papillae, divided at the tip and each portion armed with n single 

 large seta. On the outer margin of the papilla near the base is a 

 small, rounded palp-like protuberance. The second maxillae are 

 two-jointed, the basal joint stout and armed at its distal end on the 

 dorsal surface with the two claw-like processes noted by Claus as 

 characteristic of the same appendages in the copepodid female. The 

 terminal joint is also stout but smaller than the basal joint, and it 

 ends in a stout claw. 



Behind the cephalothorax come the four pairs of swimming legs, 

 the first two pairs close together and biramose, the third and fourth 

 pairs removed a very short distance and uniramose, all the rami two- 

 jointed and well supplied with setae. Color, a dark brownish red, 

 due to the contained blood ; horns dark brown ; head and ^gg strings 

 a light orange yellow. 



