iUT. 5. NORTH AMERICAN PARASITIC COPEPODS — WILSON, 29 



riorly, and a pointed angle at the center where the lateral margin 

 is drawn backward. The anterior margin projects between the in- 

 vaginations as a rounded rostrum, less than one-seventh of the length 

 of the cephalothorax. Free thorax segments fused and covered with 

 a single dorsal plate, which on the midline is the same length as the 

 head. This plate does not project at the anterior corners, but is 

 prolonged at the posterior corners into pointed processes, as long as 

 the plate itself and closely appressed to the sides of the posterior 

 body. This latter is covered with a dorsal plate as wide as long, 

 which is somewhat invaginated at the center of the posterior margin. 

 The fifth and genital segments and abdomen are entirely concealed 

 between the third and fourth legs and this dorsal plate. 



The egg strings are long and are coiled in this same space between 

 the legs and the dorsal plate, and thus out of sight. 



First antennae six-jointed, the first joint the largest, the last one 

 the smallest, all well armed with setae. Second antennae with a stout 

 and strongly curved basal joint and a short but strong terminal claw. 

 First maxillae simple, three- jointed and tipped with a small seta; 

 second maxillae and maxillipeds with stout basal joints and small 

 terminal claws. 



First swimming legs consisting of a short, rounded process tipped 

 with three protuberances, the outer one lance-shaped, the middle one 

 circular, the inner one ovate, tipped with a stout seta; second legs 

 similar. Third legs biramose, the rami flattened into laminae, the 

 outer ramus longer than the inner, the fold between the two project- 

 ing from ventral surface. Fourth legs each made up of two stout, 

 broadly oval, slightly curved laminae, the outer one the larger, each 

 ending in a flagellum. Abdomen smaller than the genital segment, 

 much wider than long ; anal laminae twice the length of the abdomen, 

 regularly tapered, five- jointed, first joint much the largest. 



Specific characters of wale. — To the generic characters already 

 noted we may add the following: General form an elongated oval, 

 the cephalo-thorax a little wider than the posterior body. Antennal 

 area projecting as in the female. First antennae twice the size of 

 those in the female. Second antennae joined at the base across the 

 midline by a chitin knob. Second maxillae and maxillipeds rela- 

 tively larger than in the female, but otherwise the same. First and 

 second swimming legs proportionally larger, but made up similarly 

 of a basal process and three protuberances ; third and fourth legs as 

 already given. 



Total length of female, 4,50 mm. ; greatest width, 1.80 mm. Total 

 length of male, 1.35 mm. ; greatest width, 0.54 mm. 



Remarhs. — This species was originally described by Kr0yer from 

 several specimens, including both sexes, obtained from the gills of 

 an undetermined species of West Indian Serranus. All other ac- 

 3136— 22— Proc.N.M.Vol.60 10 



