K0.2194. NORTH AMERICAN PARASITIC COPEPODS— WILSON. 53 



rior surface of the head, radiate the dichotomously branched soft 

 jn-ocesses, whose tips are tumid and swollen into spheres. 



These processes radiate backward along the surface of the head as 

 well as forward and sidewise, and entirely cover tli2 anterior cepha- 

 lothorax, extending back dorsally to the second antennae and ven- 

 trally to the base of the posterior horns. They thus form an ovoid 

 mass (fig. 16), the point of the oval anterior and the long axis in- 

 clined to the axis of the head. 



Anterior thorax enlarged and bent dorsally at right angles to the 

 head, then narrowed posterior to the fourth pair of Wgs into a cylin- 

 drical and chitinized neck, which is again bent at right angles, this 

 time ventrally, bringing the axis of the trunk parallel to that of the 

 head. 



Trunk cylindrical, increasing gradually to its full diameter and 

 then continuing that size throughout its entire length, with a slight 

 lobe on either side around the vulva. Abdomen hemispherical, in- 

 clined dorsally, and about one-third the diameter of the genital seg- 

 ment and one-half longer than wide. Egg strings one-fourth the 

 diameter of the trunk and one-half longer than the entire body. 



First antennae two-jointed, the terminal joints well armed with 

 setae and turned outward and downward parallel with the dorsal 

 surface of the head and at right angles to the head axis. Between 

 the bases of these antennae and projecting from the dorsal surface is 

 a small rostrum. Second antennae three-jointed, thickset, and 

 chelate. Proboscis turned down ventrally between the bases of the 

 anterior horns and consisting of a short tube somewhat enlarged at 

 the tip and nonretractile, judging by the lack of muscles. Dorsal to 

 the base of the proboscis and anterior to the end of the stomach is a 

 well-defined tripartite eye, which is not very deeply buried. On 

 either side of the proboscis near the tip is a minute two- jointed 

 maxilla, the terminal joint tipped with a short claw. 



Of the four pairs of swimming legs the first two are close together 

 and just behind the bases of the posterior horns of the head, the 

 third pair is removed a greater distance and is attached in front of 

 the groove between the third and fourth segments, while the fourth 

 pair is at a still greater distance and just in front of the beginning of 

 the neck. Each leg consists of a triangular basal joint joined to its 

 fellow by a chitin framework across the midline; each leg of the 

 first two pairs has two short rami, the third leg has but one, while 

 the fourth leg has none; the rami are indistinctly two-jointed and 

 rather heavily armed with setae. 



None of the chitin fragments of the sterna can be seen between 

 the base of the legs, as noted in C. hellottii by Jungersen (1911, p. 

 13), and no furca or longitudinal ribs similar to those found in 

 Peroderma by Richiardi. 



