472, WILLIAM NICOLL. 
1904 (= Leioderma Stafford, 1904), of which the type is 
St. furciger (Olss., 1868). The latter genus has been effi- 
ciently characterised by Odhner.' The two genera show 
unmistakable evidences of relationship, and they represent a 
type of structure distinct from that of any other sub-family 
of the Prososromata. They may therefore be regarded as the 
nucleus of a separate sub-family as already indicated by 
Odhner, and for this I propose the name FELLopIsToMIN»E 
n. subfam., with the following provisional diagnosis : 
Under middle-sized to middle-sized forms with fleshy body. 
Cuticle unarmed. Ventral sucker larger than oral sucker, 
situated about the middle of the body. Alimentary canal 
with short or nearly absent cesophagus, and diverticula not 
extending much beyond the level of the testes. Hxcretory 
vesicle Y-shaped, the fork taking place behind the ventral 
sucker and the limbs extending well into the neck. Genital 
aperture a short distance in front of the ventral sucker, median 
or to the left side. Testes symmetrical, lateral, not far 
behind the ventral sucker. Cirrus-pouch compact, bulbous, 
containing a small bipartite vesicula seminalis, a well-marked 
pars prostatica, and a short, wide ductus ejaculatorius. Ovary 
in front of right testis, multilobate. Receptaculum seminis 
absent (or present sometimes), Laurer’s canal present. Yolk- 
glands limited in extent, lateral, on each side of the ventral 
sucker. Yolk-reservoir median behind ventral sucker. Uterus 
more or less convoluted, confined between testes and genital 
aperture or extending back between testes into the posterior 
part of the body. Ova fairly numerous, measuring about *04— 
‘06 mm. by °02—05 mm. 
Type, Fellodistomum (Stafford, 1904). 
Including also Steringophorus, Odhner. 
Genus, Steringophorus Odhner, 1904. 
Steringophorus cluthensis n. sp., Pl. 10, fig. 16. 
This species was found fairly abundantly in the upper 
1“ Tyematoden d. arktischen Gebietes,” in ‘Fauna Arctica,’ iv (1904), 
p. 309. 
