^oL. 3] Esterly. — Copepod Fauna. 69 



Length: Female, 6.5 mm. 



Coloration : Whitish, translucent, and without pigment. 



Occurrence : One female, Coll. 1030. Type in the collection 

 of the University of California. 



This species resembles X. cristatus Wolfenden ( :04, p. 119, 

 pi. 9, figs. 18, 19), but differs from it in the number of joints of 

 the fifth feet, his specimen having 3-jointed feet. The fifth pair 

 being 4- jointed in X. similis makes it distinct from all other 

 species. The presence of the second row of teeth or serrations on 

 the terminal saw of the last three pairs of swimming feet is a dis- 

 tinctive character also ; at least Wolfenden does not mention such 

 a point. The anterior antennae in similis are longer than in 

 critatus. 



X. similis closely resembles Scolecithrix chelifer I. C. Thomp- 

 son ( :03, p. 21, pi. 5, figs. 1-9) in the possession of two rows of 

 teeth on the terminal saws; and the drawing Thompson gives of 

 the mandible (anterior maxilliped?) (fig. 4) is much like the an- 

 terior maxilliped in X. similis or X. cristatus Wolfenden ( :04, 

 p. 119) in the possession of the heavy hook. However, Thomp- 

 son's species has the anterior antennae 23-jointed, and the head 

 does not seem to be distinct from the thorax. These characters, 

 ^s well as the absence of the crest on the head, make it doubtful 

 if S. chelifer is the same as X. similis. 



Family CENTEOPAGIDAE. 



Cenue Metridia Boeck. 



Metridia, Giesbrecht ('92), p. 61, 339; ('98), p. 105. 

 Metridia, Esterly (:0o), p. 177. 



Metridia princeps Giesbrecht. 



PI. 11, fig. 41; pi. 13, fig. 79; pi. 14, fig. 97. 



Metridia ininceps, Giesbrecht ('92), p. 340, pi. 33, figs. 3, 18, 35, 



40; ('98), p. 107. 

 Metridia princeps, Thompson ( :03), p. 24, pi. 6, figs. 3, 4. (Male.) 



Female : Forehead seen from above is truncate, rostral fila- 

 ments borne on a papilla ; sides of last thoracic segments rounded. 

 Abdomen 3-jointed, genital segment longer than last two ; anal 



