TREBIUS. 317 



Chalimus scombri, Burm. — Carapace elongated-oval, 

 somewhat narrower in front. Thorax of four distinct seg- 

 ments. Abdomen large, of three joints. 



Hab. Belfast Bay : attached to Caligus Mullen. 



Gen. 175. TEEBIUS, Kroyer. 



Fourth pair of feet slender, and divided into two branches, 

 adapted for swimming. Thorax possessed of three distinct 

 joints. Frontal plates without sucking-discs. 



Trebius caudatus, Kroyer. — Male much smaller than 

 the female ; in the latter the carapace is oval, the first pair 

 of foot-jaws is large and strongly toothed at the apex ; the 

 abdomen is long and narrow, and ends in two small tails, 

 which have one short and three long plumose bristles. In 

 the male these tails are larger. 



Hab. Belfast Bay : on the state. First found in these 

 islands by the late Mr. Thompson. 



Fam. PANDARTB^J. 

 One of the prettiest of the families of the fish-parasites. 



