STUDIES ON THE DIGENHTIC TREMATODES. 393 
Few new results of a general nature are offered in the 
following notes. On the other hand, there are many apparent 
redundancies. These are only to be excused on the ground 
that the tendency to increased differentiation of specific forms, 
together with the fact that in numerous cases a form 
previously considered asa single species has on careful study 
of its anatomy and histology been subdivided into two or more 
distinct species, renders it necessary to give as full a descrip- 
tion of the form dealt with as possible. In this connection 
reference to a much discussed paper of Stafford’s! can hardly 
be omitted. Looss* has already expressed what must be the 
opinion of every systematist on this paper. Such a method 
as Stafford has employed is unpardonable even in a “ pre- 
liminary contribution,” and can hardly fail to cause endless 
trouble and confusion. By the laws of nomenclature Stafford’s 
generic names, except where preoccupied, must be regarded 
as valid, for he is presumed to have in his possession type- 
specimens of the several genera which he has named, or at 
any rate type-specimens must be supposed to exist somewhere.” 
For this reason Stafford’s generic name Fellodistomum 
has been adopted here, although strictly speaking the name 
Fellodistomum is really synonymous with Leioderma 
Staff. (and therefore with Steringophorus Odhn.), for there 
is absolutely no difference of generic importance in Stafford’s 
definitions of the two genera. His definition of Fello- 
distomum is actually a recapitulation of his definition of 
the preceding genus Leioderma, and the only difference is 
summed up in the sentence, “ Many resemblances to Leio- 
derma, but with sucker and genital glands crowded back- 
wards.” No mention is made of the position of the genital 
aperture, the absence of cesophagus, or the condition of the 
1 “'Trematodes from Canadian Fishes,” in ‘Zool. Anzeig.,’ xxvii (1904), 
pp. 481-495. 
= “Revision of Hemiuride,” in ‘Zool. Anzeig.,’ 
587-620. 
* Unfortunately this does not work out satisfactorily in every case. 
To my request (July, 1908) for type-specimens of several of his genera 
Dr. Stafford has vouchsafed no reply. 
xxxi (1907), pp- 
