424, WILLIAM NICOLL. 
beyond the testes; terminal part of male genital apparatus 
enclosed within a non-muscular pouch; vesicula seminalis 
convoluted; ovary immediately behind ventral sucker and 
separated from testes by considerable part of uterus; ova 
contain a Miracidium larva before deposition. Length 
‘08—10 mm. 
Type: Bunodera Raill. 
In addition to the species hitherto mentioned there are 
several other forms, mostly from America, which possess a 
row of circum-oral papille. Two of those, Distomum auri- 
culatum Wedl. and D. petalosum Lander, were regarded 
by Looss! as probable members of the genus Bunodera 
Stafford,” however, differentiated D. petalosum Lander 
(= D. auriculatum Wedl. Linton) from Bunodera, and 
proposed it as type of the new genus Acrodactyla. The 
chief features of this genus, according to Stafford, are the 
large ventral oral papille, the position of the genital 
aperture, and the large cirrus-pouch. 'l’o these I should add 
the fact that the ventral sucker is smaller than the oral. The 
structure of the cirrus-pouch and the condition of the ova are 
not noted. The limited extent of the uterus indicates that 
this genus is more nearly related to Stephanophiala and 
Crepidostomum than to Bunodera, and I have included 
it provisionally within the sub-family STEPHANOPHIALINE. 
With regard to the American forms of Distomum 
laureatum described by Linton and Stafford, it is doubt- 
ful if they are really identical with the European variety. The 
only differences which I can detect in Linton’s specimens are 
the backward position of the ovary and the slightly reduced 
number of ova. In Olsson’s figure of the species, however, 
the ovary is a little distance behind the ventral sucker, so that 
this variation may occur in the European form, The smaller 
number of ova may be only a seasonal variation. Linton 
makes no mention of the cirrus-pouch, but Stafford says it 
1 * Zool. Jahrb. Syst.,’ xvi, p. 453. 
* * Zool. Anzeiger’ (1904), xxvi, p. 491. 
