48 BRITISH PAKASIT1C COPEPODA. 



the fish. Belfast (Thompson, 1856). Plymouth 

 (Bassett- Smith). Barrow Channel, Lancashire (A. 

 Scott). Queensferry, Firth of Forth (T. Scott). 



The species does not appear to be very rare. 



Distribution. European Seas. Mediterranean 

 (Brian). 



Caligus minimus, judging 1 from the occurrences of this 

 parasite known to us, appears to be restricted almost entirely 

 to the bass. We do not know of its occurrence on any other 

 kind of fish. 



3. Caligus rapax M. Edwards.* 

 (Plate IV, figs. 3-8; Plate VI, figs. 1, 2.) 



1840. Caligu* rapax M. Edwards. (43) vol. iii, p. 453, pi. xxxviii, fig. 9. 

 1840. Caligus elungatus idem. (43) vol iii, p. 454. 

 1850. Caligus rapax Baird. (4) p. 270. pi. xxxii, figs. 2 and 3. 

 1861. Caligus rapax Stp. and Lkt. (127) p. 359. pi. ii, fig. 4. 

 1900. Caligus rapax T. Scott. (112) p. 148, pi. v. figs. 13-19. 

 1905. Caligus rapax C. B. Wilson. (145) p. 594, pi. vii, figs. 79-89. 



Female. Carapace ovate, rather longer than broad ; 

 frontal plates slightly rounded ; lunulas large and con- 

 spicuous ; thoracic area fully half the entire width of 

 the carapace ; its posterior margin broadly rounded 

 and produced somewhat beyond the narrowly-rounded 

 lateral lobes. Free thoracic segment narrow, very 

 short, and scarcely more than half the width of the 

 next one. Genital segment quadri-lateral, about as 

 long as broad and equal to about half the length of the 

 carapace. Abdomen short, unsegmented, and about 

 half the width and scarcely two-thirds the length of 

 the genital segment. Caudal rami short, and furnished 

 with moderately long plumose seta3. 



Antennules tolerably large. Antennae small, simple, 

 and armed with a small marginal tooth. Mandibles 

 elongated and narrow, terminal portion incurved and 

 toothed on the inner edge. Maxilla? small. First 

 maxillipeds slender and furnished with two slightly- 

 curved terminal claws of unequal length ; second 



* For a more detailed synonymy of this common species see 'North 

 American parasitic Copepods,' by 0. B. Wilson (Caliginse). 'Proc. U. S. 

 National Museum/ vol. xxviii, p. 568 (1905). 



