CALIGUS. 
313 
Gen. 172. CALIGUS, Muller. 
Thorax of only two distinct joints. Frontal plates with a 
small sucking-disc on the under surface of each side. Fourth 
pair of feet slender, of one branch, and used for walking. 
Caligus diaphanus, Nordmann.* — The male has the cara- 
pace large, and nearly round ; thorax much smaller than 
carapace. 
Hab. On the turbot, gurnard, mackerel, coal-fisli, cod- 
fish, and others, in Belfast Bay. 
Caligus rapax, M. Edw.- — The female has the carapace 
oval, much longer than broad ; frontal plates large and 
nearly straight in the centre ; antennae, very large. The male 
rather smaller than female, and has the last joint of thorax 
smaller ; the abdomen is longer and narrower. 
Hab. Belfast Bay : on the gurnard, John Dory, whiting, 
and other fishes. 
Caligus Mulleri, Leach. — In the female the carapace 
is oval, rather longer than broad ; the frontal plates large, 
notched in the centre. Antennm with basal joint large. 
Abdomen very short and rounded. In the male the last 
joint of thorax is smaller and more rounded. 
Hab. On cod and brill. 
