Entozoa from the Murman Coast. 511 
narrow middle portion of the ovary is a rather large shell- 
gland. Justin front of the shell-gland is a small rounded 
receptaculum seminis, 
There is no definite uterus in the gravid segments, the ova 
being scattered singly in the parenchyme. The onchospheres 
measure about 25 uw in diameter, ; 
This species bears an exceedingly -close resemblance to 
Choanotenia porosa (Rud.) in many respects, but the hooks 
are of a slightly different shape, the cirrus-sac is much 
smaller, and the uterus is not sac-like. The small number of 
segments is also a feature not characteristic of Choanotania. 
Hymenolepinida. 
‘Hymenolepis microsoma (Crepl.), Colin, 1901 (?). 
Host: Cidemia nigra (common scoter),  Yukanski, 
Seavieel GUNG. 
A number of fragments, unfortunately without scolices, 
which probably belong to this species, were the only parasites 
found in this bird. 
Hymenolepis spp. A and B, 
Host: Clangula hyemalis [=Harelda glacialis] (long- 
tailed duck). Yukanski, 8. vi. 1917. 
The collection includes portions of about three specimens of 
species of Hymenolepis from this bird. Apparently at least 
two species are represented, but the material is too frag- 
mentary for precise determination. One specimen has a 
very small scolex, with a little button-like rostellum, appa- 
rently unarmed. ‘The scolex measures 0°096 mm. across 
and the suckers only 0°03 mm. in diameter. This may be 
called species A. In the mature segments the three testes 
are arranged in a transverse row, and the fan-shaped ovary 
lies between the middle and aporal testes. ‘he entire 
spccimen is about 43 cm. in length, and the maximum width 
is about 1°5 mm. 
Another specimen, which may be called species B, has a 
larger scolex with a more typical rostellum, which was appa- 
rently provided with hooks; these, however, have all been 
Jost. The ovary, in this case, lies between the middle testis 
and that on the pore side. 
