NEMATODA 545 



The pulp of each lip has a pair of outwardly and posteriorly directed processes at its 

 anterior corners, as in the other species mentioned. There are well-developed interlabia. 

 The length of the oesophagus (in- /V 



eluding the ventriculus) is about 



1-9 mm. in the male and 2-75 mm. ////'' '- r^^'^^X^X \^ I 



in the female. The sub-globular 



ventriculus is about 0-2 mm. long / I /I /Xv ',;(..; /\ 7 \ \— CL 



in the male and 0-3 mm. in the 



female, while the intestinal caecum 



measures about o-6 and i mm. 



respectively. The nerve-ring is 



situated at 0-42 mm. from the 



anterior end in the male, and at 



about 0-65 mm. in the female. 



Well-developed cervical alae are 01 MM. 



present, the species resembling in Flg.z. Porrocaecumfalklandkum. AnterioTendoffemale, dorsal 



this respect P. semiteres rather than view, d., dorsal lip ; /., interlabium ; v., ventro-lateral lip. 



P. ensicaudatiim. 



The tail is conical in both sexes. In the male it is about 0-3 mm. long. There are 

 apparently five pairs of very small postanal papillae (of which the most posterior but one 

 is laterally situated) and some thirteen pairs of preanal papillae. The spicules are about 

 0-45 mm. long, and are apparently broadly alate, but they are retracted, and therefore 

 difficult to see clearly. Their tips are blunt. 



The tail of the female is 0-55 mm. long. The vulva is situated at 10-5 mm. from the 

 anterior extremity. The eggs are ovoid and measure o-i-o-ii mm. x o-o675-o-07 mm. 



Porrocaecum decipiens (Krabbe, 1878) (?) 



A large number of larval forms of some species of Porrocaecum, probably P. decipiens 



("Ascaris capsularia"), were collected on different occasions off South Georgia, the 



Falklands and the South Shetlands, from the peritoneum and mesenteries of various 



species of fish. The list of hosts is as follows: 



10 collections; Stations 39, 45, 123, 149, 154, MS 68, etc 



Station WS 71 



3 collections; Stations WS 73, 77 



Station 174 



Station WS 86 



Station WS 94 



Grytviken, S. Georgia 



Station 142 



These larvae were frequently accompanied by those of Contracoeciim sp. in the same 

 host. This occurred in Chompsocepholus esox, Merluccius sp., Notothenia zvilioui and 

 N. ramsoyi. In such cases it is noticeable that the Porrocaecum larvae are much longer 



Chaenocephaliis aceratiis 

 Champsocephalus esox 

 Merluccius sp. 

 Notothenia rossit (?) 

 Notothenia wiltoni 

 Notothenia ramsayi 

 Parachaenichtliys georgianus 

 "Large fish" 



