AMPHIPODS FROM NORTH AMERICAN WEST COAST — SHOEMAKER 399 



Figure 4. — Mesometopa sinuata, new species, male: a, anterior end of animal; b, epistome; 

 c, spine row of mandible; d, palp of mandible; e, gnathopod 1;/, end of gnathopod 1; g, end 

 of seventh joint of gnathopod 1; h, palm and seventh joint of gnathopod 2; i, pereopod 1; 

 /, pereopod 2; k, pereopod 4; /, pereopod 5; female: m, telson; n, end of gnathopod 2. 



joint expanded; fourth joint more expanded than that of pereopod 4, 

 with hind margin reaching down beyond middle of fifth; fifth joint 

 much shorter than sixth ; seventh joint over ji length of sixth. Seventh 

 joint of all pereopods with very fine closely set teeth on inner margin 

 (fig. 4^). Coxal plates 2-4 much deeper than their body segments, 

 increasing consecutively in depth. Coxal plate 2 reaching forward 

 to front margin of head, evenly rounding below, having several spinules 



