CONTRIBUTIONS TO AMERICAN HELMINTHOLOGY. 73 
Bitterns above referred to, along with a single male of Ascaris 
microcephala, Rud. (?) in one of these; and although closely related to 
two species (F. laticeps, R., and F. tridentata, V. Linstow®) which 
have been described from Falco lagopus on the one hand, and from 
Colymbus arcticus and Larus ridibundus on the other, it does not 
appear to resemble any of the numerous Filariz described from 
Ciconiz, except perhaps F. alata. 
I hope I may shortly have an opportunity of examining the dis- 
position of the pre- and post- anal papille in the male, a character 
of essential systematic value in this genus ; in the meantime, however, 
I record the following points which seem to distinguish it from the 
above mentioned forms : 
Densely striated. Length 10 mm.; greatest breadth, 0.43 mm. A 
cervical fascia or frill, the tops of the lateral loops of which are 
0.18 mm. from the anterior end, and which extends 0.405 mm. back- 
wards on the neck. The root of the cervical papilla (or trifurcate 
spine) is 0.06 mm. from the end of the frill. The trident measures 
from the root to the end of the median fork 0.06 mm. The eggs 
measure 0.027 mm. x0.018 mm. The tail is terminated by a short 
rounded conical projection. 
A comparison of Fig. 16 with the figures of Schneider® and V. 
Linstow, will show how it differs from the similar structures repre- 
sented there, the teeth of the trident being much longer and narrower 
in proportion to the body. The uterus was packed full of eggs, so 
that its walls were extended in every direction, occupying almost the 
whole of the body cavity. 
ANCYRACANTHUS CYSTIDICOLA (Schn.) AR. 
I find this worm very commonly present in considerable numbers 
in the swim-bladder of Salmo siscowet, Ag. The males are, how- 
ever, usually about twice (19-22 mm.) the length recorded by 
Schneider, while the females measure 30-33 mm. The two teeth 
(Fig. 17) which are doubtfully ascribed to the head by Schneider are 
quite evident in my specimens, and are continuous with two longi- 
tudinal ridges in the esophagus. It is somewhat difficult, on account 
of the coiled up tail, to get a satisfactory view of the papille in the 
male, but there seemed to be five pairs of these behind the anus. 
The eggs measure 0.04 x 0.02 mm. 
86 Trosch. Archiv., 1877, pp. 10 and 175. 
37 Loc. cit., Taf. VI., Fig. 3. 
