ISOPODS OF NORTH AMERICA. 



247 



equal width. The terminal segment is rounded posteriorly or slightly 

 triangular. The uropoda are very short, less than half the length of 

 the terminal segment; the branches are equal in length. 



FIG. 257. INDUSA CARINATA. ft, SECOND MAXILLA. 

 X 39. b, FlKST MAXILLA. X 39. C, MAXILLIPED. 



FIG. 258. INDUSA 

 X3ARINATA. LEG 

 OF SEVENTH PAIR. 



X7. 



There is a high carina on the four posterior pairs of legs, and a 

 small one on the three anterior pairs. Color reddish brown. 



Two specimens, a male and a female, were collected by Prof. C. H. 

 Gilbert from the west coast of Panama. They were found in the 

 mouth of Mugil hospes. 



7^. Cat. No. 28961, U.S.N.M. 



41. Genus CYMOTHOA Fabricius. 



Body ovate. Head more or less deeply immersed. 



First pair of antennte widely separated at the base, rather com- 

 pressed. First thoracic segment manifestly longer than the second; its 

 anterior margin more or less sinuated, with the anterior angles short 

 or produced. Epimera distinct on all the segments with the excep- 

 tion of the first; those of the first five pairs do not reach by a greater 

 or less distance the posterior angle of the segment; the posterior ones 

 reach the posterior angles of the segment or extend beyond by a small 

 distance. 



The abdomen is deeply immersed, manifestly separated from the 

 thorax, and abruptly narrower than the thorax. The legs are rather 

 short, those of the first three pairs being a little shorter than the others. 

 Carina of the four posterior pairs of legs high. 



ANALYTICAL KEY TO THE SPECIES OF THE GENUS CYMOTHOA. 



a. Antero-lateral angles of the first thoracic segment extend half the length of the 

 head or less. Eyes distinct or only traces of eyes apparent. First segment of 

 thorax one and a half times longer than second segment. Uropoda short, shorter 

 than the terminal abdominal segment. 



b. Antero-lateral angles of the first thoracic segment narrow, 

 c. Antero-lateral angles of the first thoracic segment acutely produced and reach- 

 ing the middle of head Cymothoa excim Perty 



