CESTODA. 3 
stained and fairly conspicuous. The yolk-glands are widely scattered through the 
peripheral parenchyma, 
The uterus is not fully developed in our specimens, which must be rather immature. 
It consists of few branches somewhat rosette-shaped. The ova are thin-shelled, and 
measure 0°032 by 0°028 mm. 
DIBOTHRIOCEPHALUS SCOTTI. 
The second species of Dibothriocephalus found in the alimentary measured about 
8cm. in length (fig. 3). One attained a leneth of 9em., but the other three or four 
specimens were shorter. The number of proelottides is some 150. The head is 
rounded, not at all conical, but like the amber mouthpiece of a Turkish pipe (fig. 4). 
The slit-like grooves are dorsal and ventral. The head measures Imm. across, and 
perhaps a little less from before backward. It is succeeded by a neck which, in 
some specimens, is a little narrower than the head; in others about as broad. The 
proglottides soon begin to be evident, but I do not think one can say there is no neck. 
In this respect this worm differs from D. hians of Leptonyx monachus, Wagn., Phoca 
barbata, Miill., and P. annellata, Nilss., which, in some respects, it resembles. 
The proglottides are at first some five times as broad as they are long, but sooner 
or later—and it depends upon the state of contraction of the worm when killed, how 
soon or how late—the proglottides become square, with parallel sides, and they remain 
square until the end. The posterior border is slightly thickened, and stands out at 
right angles from the body. It practically does not, however, overlap the succeeding 
proglottis. 
The reproductive organs consist of numerous testes lying scattered superficially 
through the proglottides ; the ducts of these presumably unite, though they could not 
be seen, and open into an exceeding muscular penis, which in most cases is protruded 
from the proglottis. The penis is situated in the middle line close to the anterior edge 
of the proglottis. It bears no hooks. Close behind it opens the vagina, which makes 
a coiling course backwards to where the two short oviducts from the ovary meet 
it. The ovaries are two, somewhat pear-shaped; they lie each side, near the hinder 
end of the proglottis behind the uterus, and are of fair size. A minute shell 
gland is visible at the juncture of the oviducts. No tube entering the uterus 
is visible. 
The uterus is roomy, it opens on the ventral surface in the middle line, and about 
half-way along the proglottis. The opening is circular. Just within this opening the 
uterus forms a spherical chamber, which contains a fair number of ova. From this 
chamber two or three lateral branches diverge, and these may be cut twice in one plane, 
but in no sense is the uterus rosette-shaped. 
The ova measure on an average 0°04mm. by 0°03mm., but the shape varies ; some 
