Entozoa of British }f'(rine Fishes. 17 



Zoogonus inihelluH (Olsson). (PI. I. C\'^. \.) 



o 

 DUtoma rubellian, ap. n., Olsson, Lunda Univ. Areakrift, iv. (8) p. 41, 



pi. iv. fi<r. Hi). 

 Zooffoniis tntntu, sp. n , Looss, Contmlbl. f. Bakt. xxix. pp. 439-442, 



»i-. 0. 

 '/AHu/oniu ruUUus (Olsson), OJhner, Centralbl. f. IJakt. xxxi. pp. /iO (51, 



Zooflonutt minis, has., Goldschmidt, Centralbl. f. Bakt. xxxii. pp. 870- 

 87t), fig-s. 1-t;. 



This species has been hitherto recortled only from Labridjc, 

 but I have found numerous examples in every .specimen of 

 Anarrhichas lupus in the rectum and lower part of the 

 intestine. Three excellent descriptions already exist, but 

 some doubt still remains as to whether Z. ruhellus and 

 Z. viirus are identical or not. A few differences of a minor 

 nature occur in the accounts of the above-cited authors; my 

 specimens agree best with Goldschmiilt's description. 



They are pale yellow in colour and of small size, measurln;:^ 

 for the most part 'To-l'D mm. Externally they resemble 

 Zoogonoides viviparus very much, but they are not so delicate 

 as that species. The shape is elongated oval, the greatest 

 breadth, about the level of the ventral sucker, being rather 

 less than half the length. The whole suiface of the body is 

 covered with minute regular scale-like spines. The oral 

 sucker is subterminal and globular, with a diameter of 'llo- 

 •135 mm. Tlie ventral sucker is flattened and usually iso- 

 diametric, measuring 'Ili.o-'IGS mm. In a number of 

 specimens it is contracted and distorted as in Looss's figure. 

 It thus appears smaller than the oral sucker and this may 

 account for Loess's observation. It is situated exactly r of 

 the body-length from the anterior end. The coutiguration 

 of the alimentary system conforms much more with 

 Goldschmidt's representation than with that of Looss or 

 Odhner. The prepharynx is not usually dilated and is 

 rather shorter than the pharynx. The latter is oval and 

 measures •lO-'i:') X "OS-'Oy mm. The CEsophagus is com- 

 paratively of great length and extends right behind the 

 ventral sucker before the bifurcation takes place. As a 

 matter of fact, it is difficult to say where the bifurcation 

 actually occurs, for dorsal to the ventral sucker theoesophagua 

 expands considerably, and the diverticula arise from this 

 expansion as two wide sacs. The exact point of bifurcation 

 is thus not marked oft' with such distinctiu-ss as in most other 

 species. The internal walls of the diverticula can always be 

 seen uniting just behind the posterior border of the ventral 



Anu. iC- Mag. S. Hist. Ser. 8. Vol.'w. 2 



