70 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 121 



the mandible (see fig. 6) and is composed of a basal segment bearing 

 a group of 3 short setae anteriorly and a posteriorly directed process. 

 Within the family this appendage takes 2 basic forms. In members 

 of group I, plus Nesippus, the first maxilla is represented by a basal 

 segment fused to the cephalon along its entire length and bearing a 

 group of 3 short setae and a more prominent spine, generally directed 

 posteriorly. The appendage does not appear to have much mobility 

 (see figs. 6, 75, 113, 128, 168). In the genera Pagina, Echthrogaleus, 

 Dinemoura, and Demoleus (all of group II), the first maxilla is attached 

 to the cephalon at the anterior margin of the basal segment and gives 

 the appearance of greater freedom of movement (see figs. 224, 253, 

 269). 



Second maxilla: The second maxilla in all species bears a clawlike 

 tip that usually bears rows of fringe or spinules. Group I can be 

 separated from group II by the nature of this appendage. In group I 

 there are 2 prominent spines near the base of the claw (see figs. 9, 

 76, 129, 149, 169). In group II the smaller spine is replaced by a 

 patch of setules or spinules (see figs. 204, 225, 254, 282). This 

 distinction is present in both sexes. 



Maxilliped: The maxilliped is in all species a strongly developed 

 appendage. It undoubtedly aids in holding the copepod to the host 

 or is used by the male to hold the female dm'ing copulation. It is 

 interesting to note that, in group I, 3 genera found on the body surface 

 of the host possess a maxilliped with a spatulate tip on the claw 

 (Pandarus, Pseudopandarus, and Pannosus) . This modification would 

 seem to enable the parasite to grip the denticles of the host better. 

 The remaining genus (Perissopus) of group I found on the body siu-face 

 of the host attaches by cementing the maxilliped to the host. The 2 

 genera of group I found on the giUs have pointed claws on the maxilli- 

 ped. All members of group II have sharply pointed or rounded tips 

 on the claw of the maxilliped. None are spatulate. 



Leg 1 : This appendage is relatively stable in pandarid copepods, 

 but 2 genera can be separated from the rest of the family on the basis 

 of the endopod. In Pandarus the endopod is 1-segmented. In all 

 other known members of the family the endopod is 2-segmented. 

 In Perissopus the endopod is unarmed. In all other members of the 

 family the endopod bears 3 setae. 



Leg 2: In group I the exopod of all species is 2-segmented. In 

 group II all genera have 3-segmented exopods except Demoleus and 

 Nessipus, which have only 2. 



Leg 3: The situation regarding this appendage is like that of leg 2. 

 All members of group II (except Demoleus, ^^'ith only 2) have 3- 

 segmented exopods. Copepods of group I have a 2-segmented 

 exopod except Perissopus, which has only 1. 



