NO. 1805. DESCRIPTIONS OF NEW COPEPODS— WILSON. 631 



to appear narrow in dorsal view, and without any visible transverse 

 groove; posterior lobes short and inclined outwards. No visible 

 dorsal grooves on the carapace. 



Second and third segments fused and covered with a single pair of 

 elliptical dorsal plates, wliich are entirely distinct but overlap slightly 

 at the center, and together are one-fourth wider than the carapace. 



There is also a pair of small lateral plates covering the bases of the 

 second legs, wliich are e\'idently the rudiments of another pair of 

 thoracic plates, but they are concealed beneath the posterior lobes 

 of the carapace and can not be seen except in lateral or ventral view. 



Fourth segment free, with a pair of elliptical plates similar to those 

 on the preceding segment, but a little larger. Genital segment the 

 same width as the plates on the fourth segment, one-half wider than 

 the carapace and evenly rounded; posterior sinus deep and triangu- 

 lar; posterior lobes inclined toward each other and meeting for 

 some distance. 



Abdomen attached to the ventral siu-face of the genital segment 

 in front of the posterior margin, one-jointed and triangular, one-half 

 wider than long. Anal lamina? large and evenly rounded, pro- 

 jecting slightly beyond the posterior margin of the genital segment, 

 each armed with four small spines. Egg strings narrow and straight, 

 twice as long as the entire body; eggs small and numerous. Ter- 

 minal joint of first antenna longer and narrower than the basal, with 

 a tuft of setse at its tip. 



Second antennae enlarged and ending in strong claws bent into a 

 half circle, each armed with a row of stout teeth along its ventral 

 surface near the tip. Once buried in the skin of its host, these teeth 

 act like barbs and liold the antennas securely in place. 



The mouth-tube is very pointed, with the under lip projecting 

 some distance in front of the upper one (fig. 24); the hinge is close 

 to the base of the tube. The mandibles are slender and reach the 

 very end of the mouth-tube; each is armed with a dozen large teeth 

 shaped like those on a hack saw. 



Each first maxilla forms a short and stout cone, flattened side- 

 wise, and tipped with a single small spine; on the anterior margin 

 near the tip are three small spines close together. These maxillae 

 stand out at right angles to the ventral surface of the head, while the 

 mouth- tube is nearly parallel with it (fig. 24). 



The second maxillae are of the usual pattern; the maxillipeds are 

 stout and swollen and shaped much like a pair of wide boots or 

 moccasins. The leg is the basal joint, the foot the term^inal joint; 

 from the heel projects a stout curved claw wliich shuts down against 

 the sole; the latter is flat with a raised margin, and evidently acts 

 as a suction disk to assist m attaching the parasite to its host. 



