new Parasitic Copepods on Fish. 865 



from them slender opaque white bodies, often ten from a 

 single, tumour ; on dissecting the tumours the head and neck 

 of these peculiar parasites were seen to be deeply buried, the 

 neck often being incased in a sort of red fibrinous tube ; on 

 first removing them I thought they were either Chondra- 

 canthi or one of the nearly allied genera. To the fish they 

 must be a great inconvenience, situated as they invariably 

 were. Only females were found. 



The before-mentioned authors describe the elongated portion 

 as a drawn-out posterior thoracic segment, but in these it 

 appears to be a produced neck-like commencement of the 

 true genital segment ; my specimens, too, differ in having the 

 fourth pair of thoracic legs well formed, as in Synestius, 

 Steenstrup & Liitk.*, instead of being rudimentary. 



The four-jointed fourth pair of thoracic limbs, the large 

 furcula, and the two laminate prolongations of the abdomen 

 distinguish this species. 



Female. — Lara] ace almost circular, very small, equal to 

 about one seventh of the whole animal length. Frontal 

 plate distinct, deeply excavated in the centre between the 

 two lunula?, which are of moderate size, projecting somewhat 

 in front, but less in diameter than half the frontal plate. 



Anterior antennae have a short basal joint provided with 

 the usual plumose hairs and a much longer second joint with 

 simple hairs at the end. 



Posterior antennce placed well forward near the base of 

 the rostrum ; they are three-jointed, the last joint in the form 

 of a moderately strong curved hook. 



FJamulus anterior small; it has a broad base, and is in the 

 shape of a simple short claw. 



Palp short, simple, and blunt-ended ; a second smaller 

 one is seen in front a little to the outside. 



Rostrum about twice as long as broad. 



First maxilliped of the usual form of Caligus. 



Second maxilliped powerful ; basal joint long and thick, 

 having on its inner surface a curious bifid tooth ; the terminal 

 claw is markedly curved. 



burcida very large and prominent; from a narrow neck 

 spring the two branches, which diverge widely and are sharp- 

 pointed, the width of the opening being greater than the 

 length of the arms ; seen from the side the furcula has the 

 appearance of a grapnel, being most admirably adapted for 

 fixation of the animal. Oculi of a pink colour, placed over 

 the centre of the rostrum. 



* 'Bidrag til Kundskab,' 18(51, p. 24. 



