70 BRITISH PARASITIC COPEPODA. 



Male. The male is only about half the size of the 

 female. The carapace is somewhat elliptical in out- 

 line, rather longer than broad, and equal to about two- 

 thirds of the entire length of the animal ; lateral 

 margins evenly rounded. Genital segment suborbicular 

 and equal to about one-third of the length of the 

 carapace. Abdomen about half as long as the genital 

 segment. Total length about 4 mm. 



Habitat. Parasitic on the gills of turbot, Rltombus 

 maximus (L.). North of Ireland (W. Thompson). 

 Polperro, Cornwall (A. M. Norman). Plymouth 

 (Bassett-Smith). Firths of Forth and Clyde, Aber- 

 deen, &c. (T. Scott). Irish Sea (A. Scott). 



C. B. Wilson records Lepeophtheirus thompsoni from La 

 Jolla, California, U.S.A.* 



[Lepeophtheirus obscurus Bassett-Smith. 



As there is some ambiguity concerning this form, 

 we quote the following remarks by A. M. Norman and 

 T. Scott, in ' Crustacea of Devon and Cornwall,' 

 p. 208 : " Mr. Bassett-Smith (' Journ. Marine Biol. 

 Assoc.,' vol. iv, 1896, p. 157) records a species from 

 the brill (Rhombus Isevis) taken at Plymouth, and 

 refers it with doubt to Lepeophtheirus obscurus Baird, 

 which was obtained from the same species of fish. 

 Subsequently Bassett-Smith figures what he then 

 styles C aligns obscurus Baird ('Ann. and Mag. Nat. 

 Hist.,' ser. 6, vol. xviii, pi. iv, fig. 2), and not only is 

 his parasite there referred to the genus Calif/us, but 

 the figures show the presence of sucking -disks. 

 Whether the form he found was a Lepeophtheirus or a 

 CaJigus, it was certainly not Lepeophtheirus obscurus of 

 Baird. In Bassett-Smith's third paper (' Proc. Zool. 

 Soc.,' 1899, p. 456) he referred it back again to the 

 genus Lepeophtheirus. It is just possible, if the species 

 he found was a Lepeophiheirus, that it may have been 

 the female of L. appendiculit/is Kroyer (' Naturhist. 

 Tidssk.,' ser. 3, 1863, p. 207, pi. vi, fig. 4, a-i), which 



' Proc. U. S. National Museum/ vol. xxxv, p. 441 (1908). 



