Entozoa of British Marine l-'ishi's. II3 



ventral oxcav.itioii at tlio tail. Lcnj^th G-S nun., I)rcadth 

 •S--'J mm. Cuticle aiumlatcd by furrows, uliich arc con- 

 tiuuous for more than oiieanuulus. Van Beneiliii represents 

 racii riu^ as complete, jjrohably owing to his not havin}; 

 studied the cliaraeter of the anuulation. Towards the ante- 

 rior end the furrows l)ecome faint and disappear. Projecting 

 forwaid from the liead are two small spines, omitted by 

 van Hcnedeu ; these are largest in the example from Cutius 

 biibiiUs, and aluu)st invisibk- in that from the halibut. 



'llie mouth is terminal and appears to consist of two 

 equal-sized but little-ditl'crentiatcd lips. There is a long 

 CESoidiagus and a long simple intestine pursuing an uneven 

 course towards the anus, which opens in the excavation at 

 the tail. In adult specimens the ovary and uterus occupy 

 almost the whole of the remainder of the body. The ovarv 

 arises at the posterior extremity of the body and passes 

 forward, twisting round the intestine in its course. The 

 middle third of the body is usually completely filled with ova. 

 These have the characteristic shape, with the two flagella at 

 one pole, noted by van IJeneden. Size ■039-"040 ram. x 

 •0*21 -022 mm. Tliese measurements are almost uniform in 

 the specinicns from each of the three hosts. 



A. form somewhat resembling this was taken from the 

 intestine of Pletironectes microcephalus. It displayed the 

 characteristic anmdation, but on the head, instead of two 

 spines, appeared two prominent circular marks. No ova or 

 genitalia were ])iesent, so that the specimen was immature 

 and identification was impossible. 



j:xi'laxation of the plates. 



The followii;g It-tters iqii'ly to all tlie figures : — 



BSy. Ventral eucker. PG. (Tenital aperture. 



Vn. IVnis-sac. Pli Pharvnx. 



DE. Ductus fjaculatorius. PI'h. Prepiiarynx. 



I)St. Vitflhnc glands. Pl'r. Pars pro'statica. 



Ex. Excieti.rv vesicle. Pr. Prostate glands. 



J. Iiitrstinal diverticula. 7',, 'I\. Testes. 



KSt. Ovary. -R6'. Receptaculum seminis. 



LC. Laurer's canal. I ISD. Shell-gland. 



MsX. Oral sucker. ■ Ut. Uterus. 



Or. (Ksui)hagus. [ Vg. \'agina. 



Ov. Ova. I r.V. ^'e^icula .«oniinali-». 



J'. Penis. I 



Platk I. 



Fij. 1. P' dorotyle ntinnnii, Rud. Anterior jiart, to show jtp jilnirv n\ ; 

 dorsal view. 



