46 BRITISH PARASITIC COPEPODA. 



lens, irregular stellate markings are seen scattered 

 over the surface of the carapace. 



Male. — In the male, the average dimensions of 

 which, contrary to what is usual among the Caligidse, 

 distinctly exceed those of the opposite sex, the cara- 

 pace is proportionally larger and the genital segment 

 smaller than in the female. The antennas and the 

 second maxillipecls are more robust and form more 

 powerful grasping organs. The form of the carapace 

 also differs somewhat in being proportionally wider 

 behind, and in tapering more towards the front. The 

 total lensfth of the male is about 18 mm. and the 

 width 7*5 mm., but, as in the female, the size varies 

 somewhat, ranging, according to C. B. Wilson, from 

 13 to 20 mm. in length, and from 7'4 to 11 '5 mm. in 

 width of carapace. 



Habitat. — Parasitic on various kinds of fishes, but 

 especially on Gadoids, and it has been obtained in 

 abundance along with some other species on diseased 

 cod-fishes. 



This species, first recorded by 0. F. Mill lev in 1785, is 

 regarded as the type of the genus. It is, unlike Caligus 

 rapax, rarely captured as a free-swimmer, neither is it usual 

 to find it on the gills or within the gill-covers of fishes, being 

 more frequently observed adhering to, or moving about over 

 the external surface of the fish. 



Caligus curtus is a common form around our shores, and 

 appears also to be widely distributed in the North Sea and 

 the North Atlantic. It has been recorded as abundant during 

 the autumn along the eastern sea-board of the New England 

 States of North America.* 



2. Caligus minimus Otto. 

 (Plate IV, figs. 1, 2; Plate XXV, figs. 11-16.) 



1828. Caligus minimus Otto. (93) vol. xiv, p. 354, pi. xxii, figs. 7, 8. 



1826. Caligus minimus Risso. (105) p. 135. 



1840. Caligus minutus M. Edwards. (43) vol. iii, p. 450. 



1865. Caligus minutus Heller. (58) p. 163, pi. xiv, fig. 1. 



1899. Caligus minimus Bassett-Smitli. (8) p. 447. 



* 'North American parasitic Copepods/ by C. B. Wilson (Caliginse). 

 ' Proc. U. S. National Museum/ vol. xxviii, p. 581 (1905). 



