72 CONTRIBUTIONS TO AMERICAN HELMINTHOLOGY. 
The head does not measure more than 0.5 mm. across in any of 
my preserved specimens, nor in fact does any part of the chain. In 
life it is very variable in form, and bears a distinct unarmed rostellum, 
which is frequently completed retracted, so as to escape notice, but 
acts much like a fifth sucker. This is merely indicated in Van 
Beneden’s figure,” and its existence is negatived in Diesing’s and 
Dujardin’s descriptions. 
The only ripe proglottides observed were mostly of the form repre- 
sented in Fig. 15, and measured 0.4 x 0.16 mm. Instead of containing 
a series of capsules in pairs with their contained embryos, two or 
three capsules at most were observed, with six or seven embryos 
altogether. These measured 0.027 x 0.018 mm. 
NEMATODES. 
ASCARIS ADUNCA. ud. 
A statement occurred in the “American Naturalist” in the course 
of last year, as to the prevalence of an Ascaris in the intestine of the 
American Shad—Alosa sapidissima, Storer. This was probably A. 
adunca, R. I have several specimens taken in last winter from 
Portland fish, which undoubtedly belong to this species. 
The only other reference to a round worm from the American 
Shad of which I am aware is by Dr. Leidy, who records*® Agamonema 
capsularia (?), Diesing, as free in the intestines. This, in spite of the . 
“undivided lip,” is probably the young of A. adunca, the “ obtusely 
conical, minutely mucronate tail,” arguing for this. Molin®™ describes 
“ Nematoideum Alause” also with mucronate tail, but with a four- 
papillate mouth from the European Shad, but considers that the 
absence of lips forbids its reference to A. adunca. The metamorphoses 
of the mouth-parts in Ascaris are still insufficiently known, but what 
has been already established ® does not exclude the possibility of both 
of the above larval forms belonging to A. adunca. 
FILARIA TRIAENUCHA, %. sp. 
A single female specimen of a worm belonging to the genus Filaria 
was found in the upper part of the proventriculus of each of the 
32 Mém. sur les Vers Intest., Pl. XXII., Fig. 4. 
33 Proc. Ac. Sci. Phil., VIII., p. 55. 
84 Sitz. d. k. Akad. Wien., XXXVIIL., p. 31. 
% Schneider Monog. der Nemat., p. 294. 
