548 DISCOVERY REPORTS 



end. The tail is 0-55 mm. long, conical and sharply pointed, and terminates in a small 

 spike. The body is considerably thickened in the posterior half, to which the genital 

 organs are confined. The vulva is situated at about the middle of the body, and the coils 

 of the uterine branches and ovaries extend from this level to within about 2 mm . of the anus. 

 This species differs markedly from C.fabri (Rud., 1819), which occurs in Zeus faber, 

 in the length of the intestinal caecum (see Baylis (1923 a), p. 5). 



Contracaecum sp. 



Some immature specimens of a species of Contracaecum occurred in the stomach of 

 a fin whale (Balaetioptera physaltis), at South Georgia, March 24, 1927. 



Contracaecum spp. 



Larval forms of undetermined species of Contracaecum were found very abundantly 

 in various fishes, in the peritoneal lining and mesenteries, and more particularly on the 

 surface of the liver. The list of hosts in which such larvae occurred is as follows: 



Merluccius sp. Several collections, off the Falkland Islands ; Stations WS 73 , 



76, 77, 80, 94 



Champsoceplialus esox Off the Falklands; Station WS 71 



Chaenocephahis aceratus Grytviken, S. Georgia 



Gadus sp. Off the Falklands; Station WS 99 



Notothcnia ramsayi Off the Falklands ; Station WS 94 



Notothenia wiltoni Several collections, off the Falklands; Stations WS 76, 77, 86 



Cottoperca gobio 2 collections, off the Falklands ; Stations WS 94 and 95 



Parachaenichthys georgianus Stromness, S. Georgia 



"Crocodile fish" — probably 2 collections, off South Georgia 



Parachaenichthys georgianus 



Macnironus magellanicus Off the Falklands; Station WS 92 



The general diflFerences in appearance between these Contracaecum larvae and the 

 Porrocaecum larvae with which they are often associated have already been noticed. The 

 larvae of Contracaecum frequently occur in large, tangled masses (see Fig. 3 B), in which 

 many of the individual worms, though enclosed in sheaths, do not appear to have 

 been definitely confined in capsules to one spot, but may have had a certain power of 

 movement. 



The specimens from Merluccius, Champsocephalus and Chaenocephahis appear pro- 

 bably to belong to one and the same species. Those from Notothenia wiltoni and 

 N. ramsayi probably include more than one species. 



Acanthocheilus quadridentatus (Molin, 1858) 



(Figs. 5 and 6) 



A single specimen (an immature female) taken from the stomach of Mustelus vulgaris 

 at Simonstown, South Africa, October 18, 1926, is referred somewhat doubtfully to this 

 species. Molin's (1858, 1861) description of A. quadridentatus is very brief, and his 



