336 
Entozoa of Fishes 
suspicion that the same might be said about Helicometrci flava. Three 
at least, therefore, of Stossich’s species are synonymous with each other 
and probably also with Helicometra pulchella (Rud.). 1 have as yet, 
unfortunately, not been able to examine specimens from Odhner’s 
collection. 
My specimens do not agree with Odhner’s description, but correspond 
much more closely with Stossich’s Distomum labri (1887). Considering 
that Rudolphi’s and Stossich’s specimens were collected in adjacent 
localities it is not improbable that they are identical, but that the form 
obtained by Odhner from the northern Labridae is the same species 
is somewhat doubtful. 
Species 1. Helicometra pulchella (Rud.) 1819. 
Synonyms. Distomum gobii Stossich 1883. 
Distomum labri Stossich 1883. 
Loborchis mutabilis Stossich 1902. 
Helicometra mutabilis Stossich 1903. 
This form occurred in the lower part of the intestine of Labrus 
berggylta and Conger conger, in about 60 °/ 0 of the former and 33 °/„ of 
the latter. It is usually met with in moderate numbers up to about 
twenty in a single host. It is readily distinguished in the intestinal 
contents by its rich brown colour. Young specimens, however, are 
comparatively colourless. 
Its shape is like that of most Allocreadiinae but the post- 
acetabular part is much flattened and leaf-like, with a fairly uniform 
breadth. The neck narrows gradually forwards from the ventral 
sucker, but is, as usual, capable of great extension. The length of 
adult specimens is T3—T3 mm. the average being 2 5 mm. Those 
from the conger were particularly large. In the wrasse they never 
exceeded 3 mm. and in other fishes from which I have obtained the 
species elsewhere the average size was usually about 2 mm. It 
appears to attain maturity at a size of about T25 mm. but specimens 
containing a few malformed eggs have been found as small as IT mm. 
In an average specimen of 2 5 mm. length, the maximum breadth 
at the ventral sucker is 0 - 83 mm. Both suckers are globular. The 
ventral sucker retains this shape, no matter how the animal is killed or 
pressed. In this respect it differs from other AlloCREADIINAE in 
which, during life, the ventral sucker may appear globular, but, on 
