422 WILLIAM NICOLL. 
that a somewhat broad line of separation exists between 
Stephanophiala, Acrodactyla and Crepidostomum on 
the one hand and Bunodera and Patagium on the other. 
It is unfortunate that more details are not available in the 
case of Crepidostomum, Acrodactyla, and Patagium, 
but from what is actually known it is highly probable that 
they display all the features mentioned in the following 
table : 
Stephanophiala (Crepido- Bunodera (and 
stomum and Acrodactyla?). Patagium). 
1. Testes . Directly tandem . Oblique 
2. Uterus . Confined between ventral . Extending beyond 
sucker and anterior testis testes, and even 
filling up  pos- 
terior part of 
body. 
3. Cirrus-pouch . Muscular; vesiculaseminalis . Membranous (non- 
and ductus only slightly muscular) ; vesi- 
convoluted cwa and ductus 
highly convo- 
luted. 
4. Ova . No intra-uterine segmentation. Miracidium 
larva developed 
within uterus. 
The difficulty again arises as to the precise importance to 
be attached to these differences in structure. From a study 
of the methods of classification propounded and developed 
by Looss I take it that the condition of the ova and the 
cirrus-pouch are of extreme importance, and that genera 
differing in two such essential features can hardly be 
included in the same sub-family. On examination of already 
existing and strictly demarcated sub-families it will be found 
that no such divergence in structure is to be met with. 
Amongst such sub-families, for example, as the Ecurno- 
STOMINE, ALLOCREADIINE® or GORGODERIN® with their com- 
paratively numerous members no such difference in structure 
would be admitted. From these considerations, therefore, it 
seems advisable to separate the genera Stephanophiala 
and Crepidostomum trom the sub-family Bunopgrina, 
