4 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 121 



and Echthrogaleus and have not observed this filament. More ma- 

 terial will eventually show the true nature of this structure in pandarid 

 copepods. The chalimus apparently undergoes a series of molts, in- 

 creasing the segmentation until the adult form is reached. Lewis 

 (1963) has described the life history stages of Lepeoptheirus dissimu- 

 latus Wilson. This copepod includes the following stages in its life 

 history: nauplius (first and second), copepodid (1 stage), chalimus 

 (6 stages), and adult. The life history of pandarids is probably quite 

 similar. Heegaard (1947) described 2 copepodid stages for Caligus 

 curtus (MuUer). 



The family Pandaridae is composed of 2 well-defined groups on the 

 basis of external characters of both sexes. These characters are in- 

 cluded in the key below. Group I includes the following genera: 

 Pandanis, Pseudopandarus, Phyllothyreus, Gangliopus, Perissopus, and 

 Pannosus. Group II includes: Dinemoura, Demoleus, Pagina, Ech- 

 throgaleus, Nesippus, and Paranesippus. Keys to the genera of 

 females of the 2 groups also are provided below (not enough informa- 

 tion is available to construct a key to the males). 



Key to Groups and Genera of Pandaridae 



FEMALES 



Dorsal thoracic plates present on segments 2-4; penultimate segment of second 

 maxilla with 2 prominent distal spines GROUP I 



Dorsal thoracic plates, if present, on segment 4 only; penultimate segment of 

 second maxilla with 1 spine and a patch of spinules or setules . GROUP II 



MALES 



Outer distal corner of last endopod segment of leg 3 smooth .... GROUP I 



Outer distal corner of last endopod segment of leg 3 modified with roughened 



areas and short spines GROUP II 



GENERA OF GROUP I FEMALES 



1. Dorsal thoracic plates of segment 3 extending beyond plates of segment 3 . 3 

 Dorsal thoracic plates of segment 3 not extending beyond plates of segment 



2 2 



2. Abdomen and caudal rami hidden dorsally Perissopus 



Abdomen and caudal rami visible dorsally Pandarus 



3. Plates of segment 2 large, overlapping those of segment 3 4 



Plates of segment 2 reduced and lateral to those of segment 3 5 



4. Maxilliped with spatulate tip Pannosus 



Maxilliped with pointed tip Phyllothyreus 



5. Maxilliped with pointed tip, genital segment less than }^ body length. 



Gangliopus 

 Maxilliped with spatulate tip, genital segment at least Y^ body length. 



Pseudopandarus 



