200 
New Trematodes 
sac, the unique configuration of the intestinal diverticula and the 
peculiar condition of the yolk-glands. It displays no close affinity to 
any hitherto described Trematode but for systematic purposes it may, 
for the present, be placed in the vicinity of the Haplocladinae 
(Odhner 1911). 
Zoonogenus vividus, n.g., n.sp. (PI. IX, fig. 2). 
This is neither such a remarkable, nor such an uncommon, species 
as the preceding. It was met with in two out of 11 specimens of the 
sea-bream {Spa7'us centi'odontus) examined at Aberdeen (September) 
and I have since met with it in five out of eight bream examined at 
Plymouth (July—August). It was absent, however, in half-a-dozen 
bream obtained from Billingsgate (November). Its frequency, from 
these figures, is therefore seven out of 25. 
The sea-bream does not occur in inshore waters ; it is only obtained 
at a considerable distance from the shore. For that reason all the 
specimens examined had been dead for some time, and the parasites 
were usually in a more or less macerated condition. The species, 
however, is a particularly delicate one, judging from the fact that in the 
same fishes such forms as Derogenes various and Hemiurus communis 
were still alive and active. 
This new species occurred invariably in the rectum and in no other 
part of the intestine. Only two or three specimens were found in each 
case. The worms were easily picked out by reason of their remarkably 
vivid, blood-red colour. The rectal contents of the sea-bream, partly 
from the fact that it feeds largely on Crustacea, are usually of a dull 
brownish red colour, but the colour of the parasite was much more 
intensely red. 
It is a small worm, obviously belonging to the family Zoogonidae, 
and bearing much resemblance in structure and habitat to the commoner 
and more familiar species, Zoogonoides viviparus. Its length is on an 
average 1'4 mm. and its breadth 0'46 mm. It is somewhat oval in 
outline, not much flattened, and the greatest breadth is rather behind 
the middle of the body. As already remarked, the colour is uniformly 
blood-red, but on close examination the coloration is found to be 
blotchy, much as in Zoogonoides viviparus. The cuticle is covered in 
the anterior half with minute regularly arranged spines, but these 
disappear towards the posterior end of the body. 
The oral sucker is subterminal and measures about 0T6 mm. in 
diameter. The ventral sucker is much larger, 0'34 mm. in diameter. 
