430 General Notes. [April, 
sucker is produced into papillze, and is found free in the intestinal 
canal of various European fresh-water fish (Perca, Lucioperca, Esox), 
and encysted on the outer surface of the intestine in Acerina. 
V. Linstow? indicates Paludina impura as the intermediate host 
into which the cercariæ of D. nodulosum penetrate and encyst 
themselves, Their presence in an encapsuled condition in Acerina 
he explains by supposing that the cercariz have either wandered 
directly into the little fish, or that they have been swallowed 
while still free in the mollusk. 
fresh-water fish. It remains to be seen whether the crayfish 's 
normally the intermediate host. The researches of the late Pro- 
fessor Ercolani? have shown how easily some Trematodes accom- 
modate themselves to new surroundings, and it is quite poss 
that this solitary specimen of D. nodulosum had merely | Wal 
dered” into an unaccustomed host—R. Ramsay Wright, 
of Practical Science, Toronto. 
PTEROLICHUS FALCIGER MEGNIN, OBSERVED IN TH 
States.—The “ nymphe hypopiale” ( Hypoderas columb 
g Unite? 
Murray) 
g NLU 
of this mite has been noticed by the writer on several pre 
in the tissues of the domestic pigeon. As stated by Robe 
it occurs most abundantly in the connective tissue abou 
veins near the heart, but a few may be found under the 
Nymphe hypopiale of Prerolichus falciger, enlarged 
the two posterior pairs. No mouth-parts are visible 
1 
with oe 
Arch, für Naturg., XXXIX, 18 
Tisti ‘ » 1673, P- i 
3 Dell’ adattamento della specie all’ ambiente. Bologna, 1881-2. 
