ISOPODS OF NORTH AMERICA. 



251 



distance the posterior ani;-le of the .segment; thos(^ of the lifth pair 

 ahnost reaeh the posterior angle of the segment; those of the sixth 

 pair extend a small distance l)eyond the posterior angle of the segment. 



The legs of the lirst three pairs are shorter than the others; those of 

 the last four pairs gradually but slightly increase in length. The 

 unguL'e are long, rather stout, less curved and subequal in length. 

 The carina of the four posterior pairs is high, graduall}' and greatly 

 increasing in height, the exterior angle being rounded, the posterior 

 margin more or less widely rounded. 



The abdomen is deeply immersed (less deeply immersed in the young 

 female), the inferior angles of the first segment being covered, the 

 sides of the second, third, fourth, and fifth segments together ])eing a 

 little sinuated, manifestly divergent; the abdomen is obscurely bisul- 

 cate, much wider than long (almost 5:4), two or three times shorter 

 than the thorax with the head (almost 2: 5). The first segment is cov- 

 ered for the greatest part; the second, third, and fourth segments are 

 subequal in length or graduall}' increasing a little, manifestly shorter 

 than the fifth segment. The posterior margin of 

 the first five segments is widel}^ sinuated, and 

 produced at the sides in an obtuse lobe. The 

 superior angles of the second, third, fourth, and 

 fifth segments are almost vanishing. The inferior 

 angles of the second, third, and fourth segments 

 are produced, rather acute, and decrease gradually 

 in length; those of the fifth segment are pro- 

 duced and obtusel}' rounded. 



The terminal segment is transverse, with the 

 sides rounded, the posterior margin widely sin- 

 uated, depressed at the base in the middle, 

 obscurely pitted, much wider than the fifth abdom- 

 inal segment, more than twice as wide as long 

 (7:3), and a little longer than the other abdominal 



segments together. The uropoda are equal in length to the terminal 

 segment of the abdomen; the inner branch is much shorter and a lit- 

 tle narrower than the outer branch, becoming a little narrower and 

 narrowly rounded; the outer branch is sickle shaped and posteriorly 

 narrowly rounded. 



Length of adult female 20 mm. 



Length of young female 15.5 mm. Color 3'ellow, sprinkled with 

 minute obscure spots, the spots on the head confluent in a transverse 

 row, those of the thorax confluent in a median area, with oblong waxen 

 spots remaining.'^' 



"The above description is adapted from the following one of Schiocdte and INIeinert's: 



Producte ol)ovata, compressinscula, plus duplo longior (|uani latior (9:4). Caput 



mediocre, subtrigonum, ante late rotundatum, (juam aniuUus (juartus trunci bis vel 



Fig. 261.— Cymothoa ex- 

 icuA (After Schicedte 

 AND Meinert). a, Adult 

 FEMALE, ft, Lateral VIEW 

 OF THORAX. (Both en- 

 larged.) 



