160 G. A. and W. G. MäcCallum 



The anterior end is pointed and very mobile. No buccal oriflce is 

 recognisable. Another tortuous canal is filled with eggs. The ovary 

 oviduct or Uterus is, a Single long tube making four or five turns 

 through the body, all füll of eggs which distend the body in part 

 of its length. Eggs very small, oval, yellow and extremely numerous. 

 They often contain an embryo bent on itself. 



N. guernei was found by Moniez attached by one or both ex- 

 tremities in the muscles of the inferior maxilla of Thynnus alalonga 

 the rest of the body being free. In another case they were free 

 in the intestine or caught in the mucosa, and in still others encysted 

 in pairs on the gills in cysts about the size of a pea or bean. Those 

 in the muscles measured 30 — 50 cm in length, the body elongated, 

 striated almost as though segmented, sometimes round, sometimes 

 flattened. There is a large tube opening posteriorly and stretching 

 through the whole body and seeming to open anteriorly in the 

 mouth with walls like those of the digestive tube of a nematode. 

 Anteriorly there are two distinct sexual orifices superposed, a "poche 

 peniale" prolonged by a spermiduct which separates into two immense 

 testicular tubes. From the vaginal oriflce goes an extremely long 

 folded oviduct which prolongs itself into an ovary of the same 

 general character. The water vascular System opens at the posterior 

 extremity and is prolonged as a thick walled tube without rami- 

 fications to the anterior part of the body. No other organs were 

 discoverable, Moniez thinks it possible that the smaller worms 

 (3 — 15 cm) which were found in the intestine, the encysted and the 

 intramuscular forms may represent alternations of generations. 



iV. molae is described by Maclaren from the gills of Ortha- 

 goriscus mola where it occurs encysted in pairs. It resembles N. 

 ßarina closely except in the possession of a small ventral sucker. 

 The worm is 7 cm long by 2 mm in thickness, soft irregulär in 

 form with a threadlike anterior portion and a biunter posterior end. 

 The mouth at the anterior end opens directly into the pharynx 

 without a sucker. The genital opening lies on a prominent ventral 

 Papilla about 0,6 mm from the mouth. The body is enveloped in 

 a tliin sheath. There is a rather long Oesophagus which divides 

 into two Short intestinal coeca lined with peculiar amoeboid cells. 

 The excretory canal is a Single irregulär canal opening posteriorly 

 and bifurcating anteriorly at the level of the ventral sucker. There 

 are two festes of long tortuous tubulär form stretching through 

 tlie bod}' which taper into vasa deferentia and unite into a bul- 



