SOME PARASITIC COPEPODA. 55 



have thought it better therefore provisionally to call this parasite Bmchiella parkeri, 

 Thompson. 



The structure of the tenaculum with its remarkable sucker will be described in 

 another pajoer. 



Genus Anchorella, Cuvier (1817). 

 Anchorella rtjgosa, Kroyer. (PI. 10. figs. 28-32 ; PI. 11. figs. 33-37.) 



1837. Anchorella rugosa, Kroyer, Naturh. Tidsskr. Rfekke 1, Bd. i. p. 284, pi. 2. fig. 7, pi. 3. 



figs. 14 a-e. 

 1840. Anchorella rugosa, Milne-Edwards, Hist. Nat. Crust, iii. p. 519. 

 1851. Anchorella rugosa, p. 7, Van Beneden, Arm. Sci. Nat. 3 me serie, vol. xvi. p. 114, pi. G. 



figs. 7-10. 

 1863. Anchorella rugosa, Kroyer, Naturh. Tidsskr. Rcekke 3, Bd. ii. p. 383. 

 1879. Anchorella rugosa, C. Vogt, Recherekes Cotieres faites a Roskoff ; Geneve. 



1899. Anchorella rugosa, Bassett-Smith, " A Systematic Description of Parasitic Copepoda found on 



Fishes," Proc. Zool. Soc. London, April 1899, p. 503. 



1900. Anchorella rugosa, T. Scott, 18th Ann. Rep. Fish. Board Scot. pt. iii.' p. 176, pi. 8. 



figs. 45-48. 



This species seems to be fairly common on the gills of the Catfish (Anarrhichas lupus, 

 Linn.). There is considerable variation in the size of the female. One specimen 

 measured 4 mm. from the base of the first maxillipeds to the end of the abdomen. 

 The cephalothorax measured 6 - 5 mm. in length and the width of the genital segment 

 was 36 mm. In another specimen these measures were respectively 23 mm., 4*4 mm., 

 and 2'8 mm. 



The Female. — Kroyer's description of this parasite is good, but his figures are poor. 

 T. Scott (op. cit. 1900) also gives a short account and some figures of this species. 

 The square outline of the genital segment and the stout wavy cephalothorax, which 

 in life is doubled back and lies close to the dorsal surface, are very characteristic, 

 as is also the jerky movement of the head from side to side and the slow 

 movement up and down of the ovisacs. Kroyer mentions the peculiar move- 

 ment of the end of the cephalothorax. Slighter movements of the antennae and 

 second maxillae can be seen. In life the colour of the genital segment is 

 yellowish and semi-transparent. A wide brown intestine with wavy borders runs 

 down the cephalothorax and can be seen as a conspicuous brown mass on the 

 ventral surface of the genital segment. The ova are paler in colour and each 

 shows two specks of brown pigment (February). The cbitinous structures are 

 deep yellow. On the ventral surface (the side away from the cephalothorax), just 

 anterior to the abdomen and between the ovisacs, are two yellow cbitinous spots (the 

 openings of the receptacula seminis) ; projecting from these in one specimen were 

 two semi-transparent packets in shape like long narrow pods : these are probably 

 spermatophores. On another female without ovisacs two globular semi-transparent 

 bodies were observed projecting from the openings of the oviducts. They measured 

 •66 mm. in width and were S mm. long. Possibly they are the commencement 



8* 



