SEA-FISHERIES LABORATORY. 117 



There are many different kinds of worm parasites 

 infesting local fishes, and as this group has only recently 

 been seriously investigated in our district, we expect that 

 the present list will soon be greatly extended. The 

 Cestodes and Nematodes have still to be worked out. In 

 addition to the fishes, many marine invertebrata are also 

 more or less infested with parasites, some containing im- 

 mature stages of the fish parasites. 



The Copepod parasites are almost entirely confined to 

 places in direct communication with the exterior. They 

 may be found on the skin, the fins, in the mouth and 

 branchial chamber, in the lateral line canal, attached 

 to the gills and operculum, in the nostrils, in the 

 eye and sometimes even burrowing into the abdominal 

 cavity. In many cases their life history and anato- 

 mical structure are only partly known. Some are 

 almost free, but the majority are true parasites, 

 depending entirely upon their host for food, and having 

 no means of locomotion. The males of the attached forms 

 are extremely small and easily overlooked. All hatch 

 from the egg as Xauplii and undergo very considerable 

 metamorphoses before arriving at maturity. Iu some 

 genera the development is wholly progressive. In others, 

 such as Lemcea, when a particular stage is reached it 

 becomes retrogressive. At one end of the group the para- 

 sites are practically free swimmers, and at the other they 

 are mere inert sacs whose relationship with such forms as 

 Caligus appears very remote. 



Bomolochus solece, Glaus. 



In the nostrils of cod, greater fork-beard, plaice, &c, 

 also on the skin of the common sole. A number of 

 specimens of this copepod can usually be secured by 

 forcing out the mucus from the inner part of the nostrils 

 of medium sized cod. On placing the mucus in a watch 



